Merge pull request #794 from jinzhu/v1.0_dev

The first public release

.gitignore

@@ -0,0 +1,2 @@
+documents
+_book

association.go

@@ -4,32 +4,289 @@ import (
 	"errors"
 	"fmt"
 	"reflect"
-	"strings"
 )
 
+// Association Mode contains some helper methods to handle relationship things easily.
 type Association struct {
-	Scope  *Scope
-	Column string
 	Error  error
-	Field  *Field
+	scope  *Scope
+	column string
+	field  *Field
 }
 
-func (association *Association) setErr(err error) *Association {
+// Find find out all related associations
-	if err != nil {
+func (association *Association) Find(value interface{}) *Association {
-		association.Error = err
+	association.scope.related(value, association.column)
+	return association.setErr(association.scope.db.Error)
+}
+
+// Append append new associations for many2many, has_many, replace current association for has_one, belongs_to
+func (association *Association) Append(values ...interface{}) *Association {
+	if relationship := association.field.Relationship; relationship.Kind == "has_one" {
+		return association.Replace(values...)
+	}
+	return association.saveAssociations(values...)
+}
+
+// Replace replace current associations with new one
+func (association *Association) Replace(values ...interface{}) *Association {
+	var (
+		relationship = association.field.Relationship
+		scope        = association.scope
+		field        = association.field.Field
+		newDB        = scope.NewDB()
+	)
+
+	// Append new values
+	association.field.Set(reflect.Zero(association.field.Field.Type()))
+	association.saveAssociations(values...)
+
+	// Belongs To
+	if relationship.Kind == "belongs_to" {
+		// Set foreign key to be null when clearing value (length equals 0)
+		if len(values) == 0 {
+			// Set foreign key to be nil
+			var foreignKeyMap = map[string]interface{}{}
+			for _, foreignKey := range relationship.ForeignDBNames {
+				foreignKeyMap[foreignKey] = nil
+			}
+			association.setErr(newDB.Model(scope.Value).UpdateColumn(foreignKeyMap).Error)
+		}
+	} else {
+		// Polymorphic Relations
+		if relationship.PolymorphicDBName != "" {
+			newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(relationship.PolymorphicDBName)), scope.TableName())
+		}
+
+		// Delete Relations except new created
+		if len(values) > 0 {
+			var associationForeignFieldNames []string
+			if relationship.Kind == "many_to_many" {
+				// if many to many relations, get association fields name from association foreign keys
+				associationScope := scope.New(reflect.New(field.Type()).Interface())
+				for _, dbName := range relationship.AssociationForeignFieldNames {
+					if field, ok := associationScope.FieldByName(dbName); ok {
+						associationForeignFieldNames = append(associationForeignFieldNames, field.Name)
+					}
+				}
+			} else {
+				// If other relations, use primary keys
+				for _, field := range scope.New(reflect.New(field.Type()).Interface()).PrimaryFields() {
+					associationForeignFieldNames = append(associationForeignFieldNames, field.Name)
+				}
+			}
+
+			newPrimaryKeys := scope.getColumnAsArray(associationForeignFieldNames, field.Interface())
+
+			if len(newPrimaryKeys) > 0 {
+				sql := fmt.Sprintf("%v NOT IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(newPrimaryKeys))
+				newDB = newDB.Where(sql, toQueryValues(newPrimaryKeys)...)
+			}
+		}
+
+		if relationship.Kind == "many_to_many" {
+			// if many to many relations, delete related relations from join table
+			var sourceForeignFieldNames []string
+
+			for _, dbName := range relationship.ForeignFieldNames {
+				if field, ok := scope.FieldByName(dbName); ok {
+					sourceForeignFieldNames = append(sourceForeignFieldNames, field.Name)
+				}
+			}
+
+			if sourcePrimaryKeys := scope.getColumnAsArray(sourceForeignFieldNames, scope.Value); len(sourcePrimaryKeys) > 0 {
+				newDB = newDB.Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(sourcePrimaryKeys)), toQueryValues(sourcePrimaryKeys)...)
+
+				association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, newDB, relationship))
+			}
+		} else if relationship.Kind == "has_one" || relationship.Kind == "has_many" {
+			// has_one or has_many relations, set foreign key to be nil (TODO or delete them?)
+			var foreignKeyMap = map[string]interface{}{}
+			for idx, foreignKey := range relationship.ForeignDBNames {
+				foreignKeyMap[foreignKey] = nil
+				if field, ok := scope.FieldByName(relationship.AssociationForeignFieldNames[idx]); ok {
+					newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(foreignKey)), field.Field.Interface())
+				}
+			}
+
+			fieldValue := reflect.New(association.field.Field.Type()).Interface()
+			association.setErr(newDB.Model(fieldValue).UpdateColumn(foreignKeyMap).Error)
+		}
 	}
 	return association
 }
 
-func (association *Association) Find(value interface{}) *Association {
+// Delete remove relationship between source & passed arguments, but won't delete those arguments
-	association.Scope.related(value, association.Column)
+func (association *Association) Delete(values ...interface{}) *Association {
-	return association.setErr(association.Scope.db.Error)
+	var (
+		relationship = association.field.Relationship
+		scope        = association.scope
+		field        = association.field.Field
+		newDB        = scope.NewDB()
+	)
+
+	if len(values) == 0 {
+		return association
 	}
 
+	var deletingResourcePrimaryFieldNames, deletingResourcePrimaryDBNames []string
+	for _, field := range scope.New(reflect.New(field.Type()).Interface()).PrimaryFields() {
+		deletingResourcePrimaryFieldNames = append(deletingResourcePrimaryFieldNames, field.Name)
+		deletingResourcePrimaryDBNames = append(deletingResourcePrimaryDBNames, field.DBName)
+	}
+
+	deletingPrimaryKeys := scope.getColumnAsArray(deletingResourcePrimaryFieldNames, values...)
+
+	if relationship.Kind == "many_to_many" {
+		// source value's foreign keys
+		for idx, foreignKey := range relationship.ForeignDBNames {
+			if field, ok := scope.FieldByName(relationship.ForeignFieldNames[idx]); ok {
+				newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(foreignKey)), field.Field.Interface())
+			}
+		}
+
+		// get association's foreign fields name
+		var associationScope = scope.New(reflect.New(field.Type()).Interface())
+		var associationForeignFieldNames []string
+		for _, associationDBName := range relationship.AssociationForeignFieldNames {
+			if field, ok := associationScope.FieldByName(associationDBName); ok {
+				associationForeignFieldNames = append(associationForeignFieldNames, field.Name)
+			}
+		}
+
+		// association value's foreign keys
+		deletingPrimaryKeys := scope.getColumnAsArray(associationForeignFieldNames, values...)
+		sql := fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(deletingPrimaryKeys))
+		newDB = newDB.Where(sql, toQueryValues(deletingPrimaryKeys)...)
+
+		association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, newDB, relationship))
+	} else {
+		var foreignKeyMap = map[string]interface{}{}
+		for _, foreignKey := range relationship.ForeignDBNames {
+			foreignKeyMap[foreignKey] = nil
+		}
+
+		if relationship.Kind == "belongs_to" {
+			// find with deleting relation's foreign keys
+			primaryKeys := scope.getColumnAsArray(relationship.AssociationForeignFieldNames, values...)
+			newDB = newDB.Where(
+				fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys)),
+				toQueryValues(primaryKeys)...,
+			)
+
+			// set foreign key to be null if there are some records affected
+			modelValue := reflect.New(scope.GetModelStruct().ModelType).Interface()
+			if results := newDB.Model(modelValue).UpdateColumn(foreignKeyMap); results.Error == nil {
+				if results.RowsAffected > 0 {
+					scope.updatedAttrsWithValues(foreignKeyMap)
+				}
+			} else {
+				association.setErr(results.Error)
+			}
+		} else if relationship.Kind == "has_one" || relationship.Kind == "has_many" {
+			// find all relations
+			primaryKeys := scope.getColumnAsArray(relationship.AssociationForeignFieldNames, scope.Value)
+			newDB = newDB.Where(
+				fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys)),
+				toQueryValues(primaryKeys)...,
+			)
+
+			// only include those deleting relations
+			newDB = newDB.Where(
+				fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, deletingResourcePrimaryDBNames), toQueryMarks(deletingPrimaryKeys)),
+				toQueryValues(deletingPrimaryKeys)...,
+			)
+
+			// set matched relation's foreign key to be null
+			fieldValue := reflect.New(association.field.Field.Type()).Interface()
+			association.setErr(newDB.Model(fieldValue).UpdateColumn(foreignKeyMap).Error)
+		}
+	}
+
+	// Remove deleted records from source's field
+	if association.Error == nil {
+		if field.Kind() == reflect.Slice {
+			leftValues := reflect.Zero(field.Type())
+
+			for i := 0; i < field.Len(); i++ {
+				reflectValue := field.Index(i)
+				primaryKey := scope.getColumnAsArray(deletingResourcePrimaryFieldNames, reflectValue.Interface())[0]
+				var isDeleted = false
+				for _, pk := range deletingPrimaryKeys {
+					if equalAsString(primaryKey, pk) {
+						isDeleted = true
+						break
+					}
+				}
+				if !isDeleted {
+					leftValues = reflect.Append(leftValues, reflectValue)
+				}
+			}
+
+			association.field.Set(leftValues)
+		} else if field.Kind() == reflect.Struct {
+			primaryKey := scope.getColumnAsArray(deletingResourcePrimaryFieldNames, field.Interface())[0]
+			for _, pk := range deletingPrimaryKeys {
+				if equalAsString(primaryKey, pk) {
+					association.field.Set(reflect.Zero(field.Type()))
+					break
+				}
+			}
+		}
+	}
+
+	return association
+}
+
+// Clear remove relationship between source & current associations, won't delete those associations
+func (association *Association) Clear() *Association {
+	return association.Replace()
+}
+
+// Count return the count of current associations
+func (association *Association) Count() int {
+	var (
+		count        = 0
+		relationship = association.field.Relationship
+		scope        = association.scope
+		fieldValue   = association.field.Field.Interface()
+		query        = scope.DB()
+	)
+
+	if relationship.Kind == "many_to_many" {
+		query = relationship.JoinTableHandler.JoinWith(relationship.JoinTableHandler, query, scope.Value)
+	} else if relationship.Kind == "has_many" || relationship.Kind == "has_one" {
+		primaryKeys := scope.getColumnAsArray(relationship.AssociationForeignFieldNames, scope.Value)
+		query = query.Where(
+			fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys)),
+			toQueryValues(primaryKeys)...,
+		)
+	} else if relationship.Kind == "belongs_to" {
+		primaryKeys := scope.getColumnAsArray(relationship.ForeignFieldNames, scope.Value)
+		query = query.Where(
+			fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(primaryKeys)),
+			toQueryValues(primaryKeys)...,
+		)
+	}
+
+	if relationship.PolymorphicType != "" {
+		query = query.Where(
+			fmt.Sprintf("%v.%v = ?", scope.New(fieldValue).QuotedTableName(), scope.Quote(relationship.PolymorphicDBName)),
+			scope.TableName(),
+		)
+	}
+
+	query.Model(fieldValue).Count(&count)
+	return count
+}
+
+// saveAssociations save passed values as associations
 func (association *Association) saveAssociations(values ...interface{}) *Association {
-	scope := association.Scope
+	var (
-	field := association.Field
+		scope        = association.scope
-	relationship := association.Field.Relationship
+		field        = association.field
+		relationship = field.Relationship
+	)
 
 	saveAssociation := func(reflectValue reflect.Value) {
 		// value has to been pointer
@@ -94,318 +351,9 @@ func (association *Association) saveAssociations(values ...interface{}) *Associa
 	return association
 }
 
-func (association *Association) Append(values ...interface{}) *Association {
+func (association *Association) setErr(err error) *Association {
-	if relationship := association.Field.Relationship; relationship.Kind == "has_one" {
+	if err != nil {
-		return association.Replace(values...)
+		association.Error = err
-	}
-	return association.saveAssociations(values...)
-}
-
-func (association *Association) Replace(values ...interface{}) *Association {
-	var (
-		relationship = association.Field.Relationship
-		scope        = association.Scope
-		field        = association.Field.Field
-		newDB        = scope.NewDB()
-	)
-
-	// Append new values
-	association.Field.Set(reflect.Zero(association.Field.Field.Type()))
-	association.saveAssociations(values...)
-
-	// Belongs To
-	if relationship.Kind == "belongs_to" {
-		// Set foreign key to be null only when clearing value
-		if len(values) == 0 {
-			// Set foreign key to be nil
-			var foreignKeyMap = map[string]interface{}{}
-			for _, foreignKey := range relationship.ForeignDBNames {
-				foreignKeyMap[foreignKey] = nil
-			}
-			association.setErr(newDB.Model(scope.Value).UpdateColumn(foreignKeyMap).Error)
-		}
-	} else {
-		// Relations
-		if relationship.PolymorphicDBName != "" {
-			newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(relationship.PolymorphicDBName)), scope.TableName())
-		}
-
-		// Relations except new created
-		if len(values) > 0 {
-			var newPrimaryKeys [][]interface{}
-			var associationForeignFieldNames []string
-
-			if relationship.Kind == "many_to_many" {
-				// If many to many relations, get it from foreign key
-				associationForeignFieldNames = relationship.AssociationForeignFieldNames
-			} else {
-				// If other relations, get real primary keys
-				for _, field := range scope.New(reflect.New(field.Type()).Interface()).Fields() {
-					if field.IsPrimaryKey {
-						associationForeignFieldNames = append(associationForeignFieldNames, field.Name)
-					}
-				}
-			}
-
-			newPrimaryKeys = association.getPrimaryKeys(associationForeignFieldNames, field.Interface())
-
-			if len(newPrimaryKeys) > 0 {
-				sql := fmt.Sprintf("%v NOT IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(newPrimaryKeys))
-				newDB = newDB.Where(sql, toQueryValues(newPrimaryKeys)...)
-			}
-		}
-
-		if relationship.Kind == "many_to_many" {
-			for idx, foreignKey := range relationship.ForeignDBNames {
-				if field, ok := scope.FieldByName(relationship.ForeignFieldNames[idx]); ok {
-					newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(foreignKey)), field.Field.Interface())
-				}
-			}
-
-			association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, newDB, relationship))
-		} else if relationship.Kind == "has_one" || relationship.Kind == "has_many" {
-			var foreignKeyMap = map[string]interface{}{}
-			for idx, foreignKey := range relationship.ForeignDBNames {
-				foreignKeyMap[foreignKey] = nil
-				if field, ok := scope.FieldByName(relationship.AssociationForeignFieldNames[idx]); ok {
-					newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(foreignKey)), field.Field.Interface())
-				}
-			}
-
-			fieldValue := reflect.New(association.Field.Field.Type()).Interface()
-			association.setErr(newDB.Model(fieldValue).UpdateColumn(foreignKeyMap).Error)
-		}
 	}
 	return association
 }
-
-func (association *Association) Delete(values ...interface{}) *Association {
-	var (
-		relationship = association.Field.Relationship
-		scope        = association.Scope
-		field        = association.Field.Field
-		newDB        = scope.NewDB()
-	)
-
-	if len(values) == 0 {
-		return association
-	}
-
-	var deletingResourcePrimaryFieldNames, deletingResourcePrimaryDBNames []string
-	for _, field := range scope.New(reflect.New(field.Type()).Interface()).Fields() {
-		if field.IsPrimaryKey {
-			deletingResourcePrimaryFieldNames = append(deletingResourcePrimaryFieldNames, field.Name)
-			deletingResourcePrimaryDBNames = append(deletingResourcePrimaryDBNames, field.DBName)
-		}
-	}
-
-	deletingPrimaryKeys := association.getPrimaryKeys(deletingResourcePrimaryFieldNames, values...)
-
-	if relationship.Kind == "many_to_many" {
-		// source value's foreign keys
-		for idx, foreignKey := range relationship.ForeignDBNames {
-			if field, ok := scope.FieldByName(relationship.ForeignFieldNames[idx]); ok {
-				newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(foreignKey)), field.Field.Interface())
-			}
-		}
-
-		// association value's foreign keys
-		deletingPrimaryKeys := association.getPrimaryKeys(relationship.AssociationForeignFieldNames, values...)
-		sql := fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(deletingPrimaryKeys))
-		newDB = newDB.Where(sql, toQueryValues(deletingPrimaryKeys)...)
-
-		association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, newDB, relationship))
-	} else {
-		var foreignKeyMap = map[string]interface{}{}
-		for _, foreignKey := range relationship.ForeignDBNames {
-			foreignKeyMap[foreignKey] = nil
-		}
-
-		if relationship.Kind == "belongs_to" {
-			// find with deleting relation's foreign keys
-			primaryKeys := association.getPrimaryKeys(relationship.AssociationForeignFieldNames, values...)
-			newDB = newDB.Where(
-				fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys)),
-				toQueryValues(primaryKeys)...,
-			)
-
-			// set foreign key to be null
-			modelValue := reflect.New(scope.GetModelStruct().ModelType).Interface()
-			if results := newDB.Model(modelValue).UpdateColumn(foreignKeyMap); results.Error == nil {
-				if results.RowsAffected > 0 {
-					scope.updatedAttrsWithValues(foreignKeyMap, false)
-				}
-			} else {
-				association.setErr(results.Error)
-			}
-		} else if relationship.Kind == "has_one" || relationship.Kind == "has_many" {
-			// find all relations
-			primaryKeys := association.getPrimaryKeys(relationship.AssociationForeignFieldNames, scope.Value)
-			newDB = newDB.Where(
-				fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys)),
-				toQueryValues(primaryKeys)...,
-			)
-
-			// only include those deleting relations
-			newDB = newDB.Where(
-				fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, deletingResourcePrimaryDBNames), toQueryMarks(deletingPrimaryKeys)),
-				toQueryValues(deletingPrimaryKeys)...,
-			)
-
-			// set matched relation's foreign key to be null
-			fieldValue := reflect.New(association.Field.Field.Type()).Interface()
-			association.setErr(newDB.Model(fieldValue).UpdateColumn(foreignKeyMap).Error)
-		}
-	}
-
-	// Remove deleted records from field
-	if association.Error == nil {
-		if association.Field.Field.Kind() == reflect.Slice {
-			leftValues := reflect.Zero(association.Field.Field.Type())
-
-			for i := 0; i < association.Field.Field.Len(); i++ {
-				reflectValue := association.Field.Field.Index(i)
-				primaryKey := association.getPrimaryKeys(deletingResourcePrimaryFieldNames, reflectValue.Interface())[0]
-				var included = false
-				for _, pk := range deletingPrimaryKeys {
-					if equalAsString(primaryKey, pk) {
-						included = true
-					}
-				}
-				if !included {
-					leftValues = reflect.Append(leftValues, reflectValue)
-				}
-			}
-
-			association.Field.Set(leftValues)
-		} else if association.Field.Field.Kind() == reflect.Struct {
-			primaryKey := association.getPrimaryKeys(deletingResourcePrimaryFieldNames, association.Field.Field.Interface())[0]
-			for _, pk := range deletingPrimaryKeys {
-				if equalAsString(primaryKey, pk) {
-					association.Field.Set(reflect.Zero(association.Field.Field.Type()))
-					break
-				}
-			}
-		}
-	}
-
-	return association
-}
-
-func (association *Association) Clear() *Association {
-	return association.Replace()
-}
-
-func (association *Association) Count() int {
-	var (
-		count        = 0
-		relationship = association.Field.Relationship
-		scope        = association.Scope
-		fieldValue   = association.Field.Field.Interface()
-		newScope     = scope.New(fieldValue)
-	)
-
-	if relationship.Kind == "many_to_many" {
-		relationship.JoinTableHandler.JoinWith(relationship.JoinTableHandler, scope.DB(), association.Scope.Value).Model(fieldValue).Count(&count)
-	} else if relationship.Kind == "has_many" || relationship.Kind == "has_one" {
-		query := scope.DB()
-		for idx, foreignKey := range relationship.ForeignDBNames {
-			if field, ok := scope.FieldByName(relationship.AssociationForeignDBNames[idx]); ok {
-				query = query.Where(fmt.Sprintf("%v.%v = ?", newScope.QuotedTableName(), scope.Quote(foreignKey)),
-					field.Field.Interface())
-			}
-		}
-
-		if relationship.PolymorphicType != "" {
-			query = query.Where(fmt.Sprintf("%v.%v = ?", newScope.QuotedTableName(), newScope.Quote(relationship.PolymorphicDBName)), scope.TableName())
-		}
-		query.Model(fieldValue).Count(&count)
-	} else if relationship.Kind == "belongs_to" {
-		query := scope.DB()
-		for idx, primaryKey := range relationship.AssociationForeignDBNames {
-			if field, ok := scope.FieldByName(relationship.ForeignDBNames[idx]); ok {
-				query = query.Where(fmt.Sprintf("%v.%v = ?", newScope.QuotedTableName(), scope.Quote(primaryKey)),
-					field.Field.Interface())
-			}
-		}
-		query.Model(fieldValue).Count(&count)
-	}
-
-	return count
-}
-
-func (association *Association) getPrimaryKeys(columns []string, values ...interface{}) (results [][]interface{}) {
-	scope := association.Scope
-
-	for _, value := range values {
-		reflectValue := reflect.Indirect(reflect.ValueOf(value))
-		if reflectValue.Kind() == reflect.Slice {
-			for i := 0; i < reflectValue.Len(); i++ {
-				primaryKeys := []interface{}{}
-				newScope := scope.New(reflectValue.Index(i).Interface())
-				for _, column := range columns {
-					if field, ok := newScope.FieldByName(column); ok {
-						primaryKeys = append(primaryKeys, field.Field.Interface())
-					} else {
-						primaryKeys = append(primaryKeys, "")
-					}
-				}
-				results = append(results, primaryKeys)
-			}
-		} else if reflectValue.Kind() == reflect.Struct {
-			newScope := scope.New(value)
-			var primaryKeys []interface{}
-			for _, column := range columns {
-				if field, ok := newScope.FieldByName(column); ok {
-					primaryKeys = append(primaryKeys, field.Field.Interface())
-				} else {
-					primaryKeys = append(primaryKeys, "")
-				}
-			}
-
-			results = append(results, primaryKeys)
-		}
-	}
-
-	return
-}
-
-func toQueryMarks(primaryValues [][]interface{}) string {
-	var results []string
-
-	for _, primaryValue := range primaryValues {
-		var marks []string
-		for _, _ = range primaryValue {
-			marks = append(marks, "?")
-		}
-
-		if len(marks) > 1 {
-			results = append(results, fmt.Sprintf("(%v)", strings.Join(marks, ",")))
-		} else {
-			results = append(results, strings.Join(marks, ""))
-		}
-	}
-	return strings.Join(results, ",")
-}
-
-func toQueryCondition(scope *Scope, columns []string) string {
-	var newColumns []string
-	for _, column := range columns {
-		newColumns = append(newColumns, scope.Quote(column))
-	}
-
-	if len(columns) > 1 {
-		return fmt.Sprintf("(%v)", strings.Join(newColumns, ","))
-	} else {
-		return strings.Join(newColumns, ",")
-	}
-}
-
-func toQueryValues(primaryValues [][]interface{}) (values []interface{}) {
-	for _, primaryValue := range primaryValues {
-		for _, value := range primaryValue {
-			values = append(values, value)
-		}
-	}
-	return values
-}

association_test.go

@@ -5,6 +5,8 @@ import (
 	"reflect"
 	"sort"
 	"testing"
+
+	"github.com/jinzhu/gorm"
 )
 
 func TestBelongsTo(t *testing.T) {
@@ -16,7 +18,7 @@ func TestBelongsTo(t *testing.T) {
 	}
 
 	if err := DB.Save(&post).Error; err != nil {
-		t.Errorf("Got errors when save post", err.Error())
+		t.Error("Got errors when save post", err)
 	}
 
 	if post.Category.ID == 0 || post.MainCategory.ID == 0 {
@@ -177,6 +179,49 @@ func TestBelongsTo(t *testing.T) {
 	}
 }
 
+func TestBelongsToOverrideForeignKey1(t *testing.T) {
+	type Profile struct {
+		gorm.Model
+		Name string
+	}
+
+	type User struct {
+		gorm.Model
+		Profile      Profile `gorm:"ForeignKey:ProfileRefer"`
+		ProfileRefer int
+	}
+
+	if relation, ok := DB.NewScope(&User{}).FieldByName("Profile"); ok {
+		if relation.Relationship.Kind != "belongs_to" ||
+			!reflect.DeepEqual(relation.Relationship.ForeignFieldNames, []string{"ProfileRefer"}) ||
+			!reflect.DeepEqual(relation.Relationship.AssociationForeignFieldNames, []string{"ID"}) {
+			t.Errorf("Override belongs to foreign key with tag")
+		}
+	}
+}
+
+func TestBelongsToOverrideForeignKey2(t *testing.T) {
+	type Profile struct {
+		gorm.Model
+		Refer string
+		Name  string
+	}
+
+	type User struct {
+		gorm.Model
+		Profile   Profile `gorm:"ForeignKey:ProfileID;AssociationForeignKey:Refer"`
+		ProfileID int
+	}
+
+	if relation, ok := DB.NewScope(&User{}).FieldByName("Profile"); ok {
+		if relation.Relationship.Kind != "belongs_to" ||
+			!reflect.DeepEqual(relation.Relationship.ForeignFieldNames, []string{"ProfileID"}) ||
+			!reflect.DeepEqual(relation.Relationship.AssociationForeignFieldNames, []string{"Refer"}) {
+			t.Errorf("Override belongs to foreign key with tag")
+		}
+	}
+}
+
 func TestHasOne(t *testing.T) {
 	user := User{
 		Name:       "has one",
@@ -184,7 +229,7 @@ func TestHasOne(t *testing.T) {
 	}
 
 	if err := DB.Save(&user).Error; err != nil {
-		t.Errorf("Got errors when save user", err.Error())
+		t.Error("Got errors when save user", err.Error())
 	}
 
 	if user.CreditCard.UserId.Int64 == 0 {
@@ -323,6 +368,49 @@ func TestHasOne(t *testing.T) {
 	}
 }
 
+func TestHasOneOverrideForeignKey1(t *testing.T) {
+	type Profile struct {
+		gorm.Model
+		Name      string
+		UserRefer uint
+	}
+
+	type User struct {
+		gorm.Model
+		Profile Profile `gorm:"ForeignKey:UserRefer"`
+	}
+
+	if relation, ok := DB.NewScope(&User{}).FieldByName("Profile"); ok {
+		if relation.Relationship.Kind != "has_one" ||
+			!reflect.DeepEqual(relation.Relationship.ForeignFieldNames, []string{"UserRefer"}) ||
+			!reflect.DeepEqual(relation.Relationship.AssociationForeignFieldNames, []string{"ID"}) {
+			t.Errorf("Override belongs to foreign key with tag")
+		}
+	}
+}
+
+func TestHasOneOverrideForeignKey2(t *testing.T) {
+	type Profile struct {
+		gorm.Model
+		Name   string
+		UserID uint
+	}
+
+	type User struct {
+		gorm.Model
+		Refer   string
+		Profile Profile `gorm:"ForeignKey:UserID;AssociationForeignKey:Refer"`
+	}
+
+	if relation, ok := DB.NewScope(&User{}).FieldByName("Profile"); ok {
+		if relation.Relationship.Kind != "has_one" ||
+			!reflect.DeepEqual(relation.Relationship.ForeignFieldNames, []string{"UserID"}) ||
+			!reflect.DeepEqual(relation.Relationship.AssociationForeignFieldNames, []string{"Refer"}) {
+			t.Errorf("Override belongs to foreign key with tag")
+		}
+	}
+}
+
 func TestHasMany(t *testing.T) {
 	post := Post{
 		Title:    "post has many",
@@ -331,7 +419,7 @@ func TestHasMany(t *testing.T) {
 	}
 
 	if err := DB.Save(&post).Error; err != nil {
-		t.Errorf("Got errors when save post", err.Error())
+		t.Error("Got errors when save post", err)
 	}
 
 	for _, comment := range post.Comments {
@@ -462,6 +550,49 @@ func TestHasMany(t *testing.T) {
 	}
 }
 
+func TestHasManyOverrideForeignKey1(t *testing.T) {
+	type Profile struct {
+		gorm.Model
+		Name      string
+		UserRefer uint
+	}
+
+	type User struct {
+		gorm.Model
+		Profile []Profile `gorm:"ForeignKey:UserRefer"`
+	}
+
+	if relation, ok := DB.NewScope(&User{}).FieldByName("Profile"); ok {
+		if relation.Relationship.Kind != "has_many" ||
+			!reflect.DeepEqual(relation.Relationship.ForeignFieldNames, []string{"UserRefer"}) ||
+			!reflect.DeepEqual(relation.Relationship.AssociationForeignFieldNames, []string{"ID"}) {
+			t.Errorf("Override belongs to foreign key with tag")
+		}
+	}
+}
+
+func TestHasManyOverrideForeignKey2(t *testing.T) {
+	type Profile struct {
+		gorm.Model
+		Name   string
+		UserID uint
+	}
+
+	type User struct {
+		gorm.Model
+		Refer   string
+		Profile []Profile `gorm:"ForeignKey:UserID;AssociationForeignKey:Refer"`
+	}
+
+	if relation, ok := DB.NewScope(&User{}).FieldByName("Profile"); ok {
+		if relation.Relationship.Kind != "has_many" ||
+			!reflect.DeepEqual(relation.Relationship.ForeignFieldNames, []string{"UserID"}) ||
+			!reflect.DeepEqual(relation.Relationship.AssociationForeignFieldNames, []string{"Refer"}) {
+			t.Errorf("Override belongs to foreign key with tag")
+		}
+	}
+}
+
 func TestManyToMany(t *testing.T) {
 	DB.Raw("delete from languages")
 	var languages = []Language{{Name: "ZH"}, {Name: "EN"}}

callback.go

@@ -4,34 +4,39 @@ import (
 	"fmt"
 )
 
-type callback struct {
+// DefaultCallback default callbacks defined by gorm
+var DefaultCallback = &Callback{}
+
+// Callback is a struct that contains all CURD callbacks
+//   Field `creates` contains callbacks will be call when creating object
+//   Field `updates` contains callbacks will be call when updating object
+//   Field `deletes` contains callbacks will be call when deleting object
+//   Field `queries` contains callbacks will be call when querying object with query methods like Find, First, Related, Association...
+//   Field `rowQueries` contains callbacks will be call when querying object with Row, Rows...
+//   Field `processors` contains all callback processors, will be used to generate above callbacks in order
+type Callback struct {
 	creates    []*func(scope *Scope)
 	updates    []*func(scope *Scope)
 	deletes    []*func(scope *Scope)
 	queries    []*func(scope *Scope)
 	rowQueries []*func(scope *Scope)
-	processors []*callbackProcessor
+	processors []*CallbackProcessor
 }
 
-type callbackProcessor struct {
+// CallbackProcessor contains callback informations
-	name      string
+type CallbackProcessor struct {
-	before    string
+	name      string              // current callback's name
-	after     string
+	before    string              // register current callback before a callback
-	replace   bool
+	after     string              // register current callback after a callback
-	remove    bool
+	replace   bool                // replace callbacks with same name
-	typ       string
+	remove    bool                // delete callbacks with same name
-	processor *func(scope *Scope)
+	kind      string              // callback type: create, update, delete, query, row_query
-	callback  *callback
+	processor *func(scope *Scope) // callback handler
+	parent    *Callback
 }
 
-func (c *callback) addProcessor(typ string) *callbackProcessor {
+func (c *Callback) clone() *Callback {
-	cp := &callbackProcessor{typ: typ, callback: c}
+	return &Callback{
-	c.processors = append(c.processors, cp)
-	return cp
-}
-
-func (c *callback) clone() *callback {
-	return &callback{
 		creates:    c.creates,
 		updates:    c.updates,
 		deletes:    c.deletes,
@@ -40,57 +45,95 @@ func (c *callback) clone() *callback {
 	}
 }
 
-func (c *callback) Create() *callbackProcessor {
+// Create could be used to register callbacks for creating object
-	return c.addProcessor("create")
+//     db.Callback().Create().After("gorm:create").Register("plugin:run_after_create", func(*Scope) {
+//       // business logic
+//       ...
+//
+//       // set error if some thing wrong happened, will rollback the creating
+//       scope.Err(errors.New("error"))
+//     })
+func (c *Callback) Create() *CallbackProcessor {
+	return &CallbackProcessor{kind: "create", parent: c}
 }
 
-func (c *callback) Update() *callbackProcessor {
+// Update could be used to register callbacks for updating object, refer `Create` for usage
-	return c.addProcessor("update")
+func (c *Callback) Update() *CallbackProcessor {
+	return &CallbackProcessor{kind: "update", parent: c}
 }
 
-func (c *callback) Delete() *callbackProcessor {
+// Delete could be used to register callbacks for deleting object, refer `Create` for usage
-	return c.addProcessor("delete")
+func (c *Callback) Delete() *CallbackProcessor {
+	return &CallbackProcessor{kind: "delete", parent: c}
 }
 
-func (c *callback) Query() *callbackProcessor {
+// Query could be used to register callbacks for querying objects with query methods like `Find`, `First`, `Related`, `Association`...
-	return c.addProcessor("query")
+// Refer `Create` for usage
+func (c *Callback) Query() *CallbackProcessor {
+	return &CallbackProcessor{kind: "query", parent: c}
 }
 
-func (c *callback) RowQuery() *callbackProcessor {
+// RowQuery could be used to register callbacks for querying objects with `Row`, `Rows`, refer `Create` for usage
-	return c.addProcessor("row_query")
+func (c *Callback) RowQuery() *CallbackProcessor {
+	return &CallbackProcessor{kind: "row_query", parent: c}
 }
 
-func (cp *callbackProcessor) Before(name string) *callbackProcessor {
+// After insert a new callback after callback `callbackName`, refer `Callbacks.Create`
-	cp.before = name
+func (cp *CallbackProcessor) After(callbackName string) *CallbackProcessor {
+	cp.after = callbackName
 	return cp
 }
 
-func (cp *callbackProcessor) After(name string) *callbackProcessor {
+// Before insert a new callback before callback `callbackName`, refer `Callbacks.Create`
-	cp.after = name
+func (cp *CallbackProcessor) Before(callbackName string) *CallbackProcessor {
+	cp.before = callbackName
 	return cp
 }
 
-func (cp *callbackProcessor) Register(name string, fc func(scope *Scope)) {
+// Register a new callback, refer `Callbacks.Create`
-	cp.name = name
+func (cp *CallbackProcessor) Register(callbackName string, callback func(scope *Scope)) {
-	cp.processor = &fc
+	cp.name = callbackName
-	cp.callback.sort()
+	cp.processor = &callback
+	cp.parent.processors = append(cp.parent.processors, cp)
+	cp.parent.reorder()
 }
 
-func (cp *callbackProcessor) Remove(name string) {
+// Remove a registered callback
-	fmt.Printf("[info] removing callback `%v` from %v\n", name, fileWithLineNum())
+//     db.Callback().Create().Remove("gorm:update_time_stamp_when_create")
-	cp.name = name
+func (cp *CallbackProcessor) Remove(callbackName string) {
+	fmt.Printf("[info] removing callback `%v` from %v\n", callbackName, fileWithLineNum())
+	cp.name = callbackName
 	cp.remove = true
-	cp.callback.sort()
+	cp.parent.processors = append(cp.parent.processors, cp)
+	cp.parent.reorder()
 }
 
-func (cp *callbackProcessor) Replace(name string, fc func(scope *Scope)) {
+// Replace a registered callback with new callback
-	fmt.Printf("[info] replacing callback `%v` from %v\n", name, fileWithLineNum())
+//     db.Callback().Create().Replace("gorm:update_time_stamp_when_create", func(*Scope) {
-	cp.name = name
+//		   scope.SetColumn("Created", now)
-	cp.processor = &fc
+//		   scope.SetColumn("Updated", now)
+//     })
+func (cp *CallbackProcessor) Replace(callbackName string, callback func(scope *Scope)) {
+	fmt.Printf("[info] replacing callback `%v` from %v\n", callbackName, fileWithLineNum())
+	cp.name = callbackName
+	cp.processor = &callback
 	cp.replace = true
-	cp.callback.sort()
+	cp.parent.processors = append(cp.parent.processors, cp)
+	cp.parent.reorder()
 }
 
+// Get registered callback
+//    db.Callback().Create().Get("gorm:create")
+func (cp *CallbackProcessor) Get(callbackName string) (callback func(scope *Scope)) {
+	for _, p := range cp.parent.processors {
+		if p.name == callbackName && p.kind == cp.kind && !cp.remove {
+			return *p.processor
+		}
+	}
+	return nil
+}
+
+// getRIndex get right index from string slice
 func getRIndex(strs []string, str string) int {
 	for i := len(strs) - 1; i >= 0; i-- {
 		if strs[i] == str {
@@ -100,83 +143,77 @@ func getRIndex(strs []string, str string) int {
 	return -1
 }
 
-func sortProcessors(cps []*callbackProcessor) []*func(scope *Scope) {
+// sortProcessors sort callback processors based on its before, after, remove, replace
-	var sortCallbackProcessor func(c *callbackProcessor)
+func sortProcessors(cps []*CallbackProcessor) []*func(scope *Scope) {
-	var names, sortedNames = []string{}, []string{}
+	var (
+		allNames, sortedNames []string
+		sortCallbackProcessor func(c *CallbackProcessor)
+	)
 
 	for _, cp := range cps {
-		if index := getRIndex(names, cp.name); index > -1 {
+		// show warning message the callback name already exists
-			if !cp.replace && !cp.remove {
+		if index := getRIndex(allNames, cp.name); index > -1 && !cp.replace && !cp.remove {
 			fmt.Printf("[warning] duplicated callback `%v` from %v\n", cp.name, fileWithLineNum())
 		}
-		}
+		allNames = append(allNames, cp.name)
-		names = append(names, cp.name)
 	}
 
-	sortCallbackProcessor = func(c *callbackProcessor) {
+	sortCallbackProcessor = func(c *CallbackProcessor) {
-		if getRIndex(sortedNames, c.name) > -1 {
+		if getRIndex(sortedNames, c.name) == -1 { // if not sorted
-			return
+			if c.before != "" { // if defined before callback
-		}
+				if index := getRIndex(sortedNames, c.before); index != -1 {
-
+					// if before callback already sorted, append current callback just after it
-		if len(c.before) > 0 {
-			if index := getRIndex(sortedNames, c.before); index > -1 {
 					sortedNames = append(sortedNames[:index], append([]string{c.name}, sortedNames[index:]...)...)
-			} else if index := getRIndex(names, c.before); index > -1 {
+				} else if index := getRIndex(allNames, c.before); index != -1 {
+					// if before callback exists but haven't sorted, append current callback to last
 					sortedNames = append(sortedNames, c.name)
 					sortCallbackProcessor(cps[index])
-			} else {
-				sortedNames = append(sortedNames, c.name)
 				}
 			}
 
-		if len(c.after) > 0 {
+			if c.after != "" { // if defined after callback
-			if index := getRIndex(sortedNames, c.after); index > -1 {
+				if index := getRIndex(sortedNames, c.after); index != -1 {
+					// if after callback already sorted, append current callback just before it
 					sortedNames = append(sortedNames[:index+1], append([]string{c.name}, sortedNames[index+1:]...)...)
-			} else if index := getRIndex(names, c.after); index > -1 {
+				} else if index := getRIndex(allNames, c.after); index != -1 {
+					// if after callback exists but haven't sorted
 					cp := cps[index]
-				if len(cp.before) == 0 {
+					// set after callback's before callback to current callback
+					if cp.before == "" {
 						cp.before = c.name
 					}
 					sortCallbackProcessor(cp)
-			} else {
-				sortedNames = append(sortedNames, c.name)
 				}
 			}
 
+			// if current callback haven't been sorted, append it to last
 			if getRIndex(sortedNames, c.name) == -1 {
 				sortedNames = append(sortedNames, c.name)
 			}
 		}
+	}
 
 	for _, cp := range cps {
 		sortCallbackProcessor(cp)
 	}
 
-	var funcs = []*func(scope *Scope){}
+	var sortedFuncs []*func(scope *Scope)
-	var sortedFuncs = []*func(scope *Scope){}
 	for _, name := range sortedNames {
-		index := getRIndex(names, name)
+		if index := getRIndex(allNames, name); !cps[index].remove {
-		if !cps[index].remove {
 			sortedFuncs = append(sortedFuncs, cps[index].processor)
 		}
 	}
 
-	for _, cp := range cps {
+	return sortedFuncs
-		if sindex := getRIndex(sortedNames, cp.name); sindex == -1 {
-			if !cp.remove {
-				funcs = append(funcs, cp.processor)
-			}
-		}
 }
 
-	return append(sortedFuncs, funcs...)
+// reorder all registered processors, and reset CURD callbacks
-}
+func (c *Callback) reorder() {
-
+	var creates, updates, deletes, queries, rowQueries []*CallbackProcessor
-func (c *callback) sort() {
-	var creates, updates, deletes, queries, rowQueries []*callbackProcessor
 
 	for _, processor := range c.processors {
-		switch processor.typ {
+		if processor.name != "" {
+			switch processor.kind {
 			case "create":
 				creates = append(creates, processor)
 			case "update":
@@ -189,6 +226,7 @@ func (c *callback) sort() {
 				rowQueries = append(rowQueries, processor)
 			}
 		}
+	}
 
 	c.creates = sortProcessors(creates)
 	c.updates = sortProcessors(updates)
@@ -196,5 +234,3 @@ func (c *callback) sort() {
 	c.queries = sortProcessors(queries)
 	c.rowQueries = sortProcessors(rowQueries)
 }
-
-var DefaultCallback = &callback{processors: []*callbackProcessor{}}

callback_create.go

@@ -5,12 +5,31 @@ import (
 	"strings"
 )
 
-func BeforeCreate(scope *Scope) {
+// Define callbacks for creating
-	scope.CallMethodWithErrorCheck("BeforeSave")
+func init() {
-	scope.CallMethodWithErrorCheck("BeforeCreate")
+	DefaultCallback.Create().Register("gorm:begin_transaction", beginTransactionCallback)
+	DefaultCallback.Create().Register("gorm:before_create", beforeCreateCallback)
+	DefaultCallback.Create().Register("gorm:save_before_associations", saveBeforeAssociationsCallback)
+	DefaultCallback.Create().Register("gorm:update_time_stamp", updateTimeStampForCreateCallback)
+	DefaultCallback.Create().Register("gorm:create", createCallback)
+	DefaultCallback.Create().Register("gorm:force_reload_after_create", forceReloadAfterCreateCallback)
+	DefaultCallback.Create().Register("gorm:save_after_associations", saveAfterAssociationsCallback)
+	DefaultCallback.Create().Register("gorm:after_create", afterCreateCallback)
+	DefaultCallback.Create().Register("gorm:commit_or_rollback_transaction", commitOrRollbackTransactionCallback)
 }
 
-func UpdateTimeStampWhenCreate(scope *Scope) {
+// beforeCreateCallback will invoke `BeforeSave`, `BeforeCreate` method before creating
+func beforeCreateCallback(scope *Scope) {
+	if !scope.HasError() {
+		scope.CallMethod("BeforeSave")
+	}
+	if !scope.HasError() {
+		scope.CallMethod("BeforeCreate")
+	}
+}
+
+// updateTimeStampForCreateCallback will set `CreatedAt`, `UpdatedAt` when creating
+func updateTimeStampForCreateCallback(scope *Scope) {
 	if !scope.HasError() {
 		now := NowFunc()
 		scope.SetColumn("CreatedAt", now)
@@ -18,109 +37,108 @@ func UpdateTimeStampWhenCreate(scope *Scope) {
 	}
 }
 
-func Create(scope *Scope) {
+// createCallback the callback used to insert data into database
-	defer scope.Trace(NowFunc())
+func createCallback(scope *Scope) {
-
 	if !scope.HasError() {
-		// set create sql
+		defer scope.trace(NowFunc())
-		var sqls, columns []string
+
-		fields := scope.Fields()
+		var (
-		for _, field := range fields {
+			columns, placeholders        []string
+			blankColumnsWithDefaultValue []string
+		)
+
+		for _, field := range scope.Fields() {
 			if scope.changeableField(field) {
 				if field.IsNormal {
-					if !field.IsPrimaryKey || (field.IsPrimaryKey && !field.IsBlank) {
+					if !field.IsPrimaryKey || !field.IsBlank {
-						if !field.IsBlank || !field.HasDefaultValue {
+						if field.IsBlank && field.HasDefaultValue {
+							blankColumnsWithDefaultValue = append(blankColumnsWithDefaultValue, field.DBName)
+							scope.InstanceSet("gorm:blank_columns_with_default_value", blankColumnsWithDefaultValue)
+						} else {
 							columns = append(columns, scope.Quote(field.DBName))
-							sqls = append(sqls, scope.AddToVars(field.Field.Interface()))
+							placeholders = append(placeholders, scope.AddToVars(field.Field.Interface()))
-						} else if field.HasDefaultValue {
-							var hasDefaultValueColumns []string
-							if oldHasDefaultValueColumns, ok := scope.InstanceGet("gorm:force_reload_after_create_attrs"); ok {
-								hasDefaultValueColumns = oldHasDefaultValueColumns.([]string)
-							}
-							hasDefaultValueColumns = append(hasDefaultValueColumns, field.DBName)
-							scope.InstanceSet("gorm:force_reload_after_create_attrs", hasDefaultValueColumns)
 						}
 					}
-				} else if relationship := field.Relationship; relationship != nil && relationship.Kind == "belongs_to" {
+				} else if field.Relationship != nil && field.Relationship.Kind == "belongs_to" {
-					for _, dbName := range relationship.ForeignDBNames {
+					for _, foreignKey := range field.Relationship.ForeignDBNames {
-						if relationField := fields[dbName]; !scope.changeableField(relationField) {
+						if foreignField, ok := scope.FieldByName(foreignKey); ok && !scope.changeableField(foreignField) {
-							columns = append(columns, scope.Quote(relationField.DBName))
+							columns = append(columns, scope.Quote(foreignField.DBName))
-							sqls = append(sqls, scope.AddToVars(relationField.Field.Interface()))
+							placeholders = append(placeholders, scope.AddToVars(foreignField.Field.Interface()))
 						}
 					}
 				}
 			}
 		}
 
-		returningKey := "*"
+		var (
-		primaryField := scope.PrimaryField()
+			returningColumn = "*"
-		if primaryField != nil {
+			quotedTableName = scope.QuotedTableName()
-			returningKey = scope.Quote(primaryField.DBName)
+			primaryField    = scope.PrimaryField()
+			extraOption     string
+		)
+
+		if str, ok := scope.Get("gorm:insert_option"); ok {
+			extraOption = fmt.Sprint(str)
 		}
 
+		if primaryField != nil {
+			returningColumn = scope.Quote(primaryField.DBName)
+		}
+
+		lastInsertIDReturningSuffix := scope.Dialect().LastInsertIDReturningSuffix(quotedTableName, returningColumn)
+
 		if len(columns) == 0 {
-			scope.Raw(fmt.Sprintf("INSERT INTO %v DEFAULT VALUES %v",
+			scope.Raw(fmt.Sprintf(
-				scope.QuotedTableName(),
+				"INSERT INTO %v DEFAULT VALUES%v%v",
-				scope.Dialect().ReturningStr(scope.QuotedTableName(), returningKey),
+				quotedTableName,
+				addExtraSpaceIfExist(extraOption),
+				addExtraSpaceIfExist(lastInsertIDReturningSuffix),
 			))
 		} else {
 			scope.Raw(fmt.Sprintf(
-				"INSERT INTO %v (%v) VALUES (%v) %v",
+				"INSERT INTO %v (%v) VALUES (%v)%v%v",
 				scope.QuotedTableName(),
 				strings.Join(columns, ","),
-				strings.Join(sqls, ","),
+				strings.Join(placeholders, ","),
-				scope.Dialect().ReturningStr(scope.QuotedTableName(), returningKey),
+				addExtraSpaceIfExist(extraOption),
+				addExtraSpaceIfExist(lastInsertIDReturningSuffix),
 			))
 		}
 
 		// execute create sql
-		if scope.Dialect().SupportLastInsertId() {
+		if lastInsertIDReturningSuffix == "" || primaryField == nil {
-			if result, err := scope.SqlDB().Exec(scope.Sql, scope.SqlVars...); scope.Err(err) == nil {
+			if result, err := scope.SQLDB().Exec(scope.SQL, scope.SQLVars...); scope.Err(err) == nil {
-				id, err := result.LastInsertId()
+				// set rows affected count
-				if scope.Err(err) == nil {
 				scope.db.RowsAffected, _ = result.RowsAffected()
+
+				// set primary value to primary field
 				if primaryField != nil && primaryField.IsBlank {
-						scope.Err(scope.SetColumn(primaryField, id))
+					if primaryValue, err := result.LastInsertId(); scope.Err(err) == nil {
+						scope.Err(primaryField.Set(primaryValue))
 					}
 				}
 			}
 		} else {
-			if primaryField == nil {
+			if err := scope.SQLDB().QueryRow(scope.SQL, scope.SQLVars...).Scan(primaryField.Field.Addr().Interface()); scope.Err(err) == nil {
-				if results, err := scope.SqlDB().Exec(scope.Sql, scope.SqlVars...); err == nil {
-					scope.db.RowsAffected, _ = results.RowsAffected()
-				} else {
-					scope.Err(err)
-				}
-			} else {
-				if err := scope.Err(scope.SqlDB().QueryRow(scope.Sql, scope.SqlVars...).Scan(primaryField.Field.Addr().Interface())); err == nil {
 				scope.db.RowsAffected = 1
-				} else {
-					scope.Err(err)
-				}
 			}
 		}
 	}
 }
 
-func ForceReloadAfterCreate(scope *Scope) {
+// forceReloadAfterCreateCallback will reload columns that having default value, and set it back to current object
-	if columns, ok := scope.InstanceGet("gorm:force_reload_after_create_attrs"); ok {
+func forceReloadAfterCreateCallback(scope *Scope) {
-		scope.DB().New().Select(columns.([]string)).First(scope.Value)
+	if blankColumnsWithDefaultValue, ok := scope.InstanceGet("gorm:blank_columns_with_default_value"); ok {
+		scope.DB().New().Select(blankColumnsWithDefaultValue.([]string)).First(scope.Value)
 	}
 }
 
-func AfterCreate(scope *Scope) {
+// afterCreateCallback will invoke `AfterCreate`, `AfterSave` method after creating
-	scope.CallMethodWithErrorCheck("AfterCreate")
+func afterCreateCallback(scope *Scope) {
-	scope.CallMethodWithErrorCheck("AfterSave")
+	if !scope.HasError() {
+		scope.CallMethod("AfterCreate")
+	}
+	if !scope.HasError() {
+		scope.CallMethod("AfterSave")
 	}
-
-func init() {
-	DefaultCallback.Create().Register("gorm:begin_transaction", BeginTransaction)
-	DefaultCallback.Create().Register("gorm:before_create", BeforeCreate)
-	DefaultCallback.Create().Register("gorm:save_before_associations", SaveBeforeAssociations)
-	DefaultCallback.Create().Register("gorm:update_time_stamp_when_create", UpdateTimeStampWhenCreate)
-	DefaultCallback.Create().Register("gorm:create", Create)
-	DefaultCallback.Create().Register("gorm:force_reload_after_create", ForceReloadAfterCreate)
-	DefaultCallback.Create().Register("gorm:save_after_associations", SaveAfterAssociations)
-	DefaultCallback.Create().Register("gorm:after_create", AfterCreate)
-	DefaultCallback.Create().Register("gorm:commit_or_rollback_transaction", CommitOrRollbackTransaction)
 }

callback_delete.go

@@ -2,35 +2,52 @@ package gorm
 
 import "fmt"
 
-func BeforeDelete(scope *Scope) {
+// Define callbacks for deleting
-	scope.CallMethodWithErrorCheck("BeforeDelete")
+func init() {
+	DefaultCallback.Delete().Register("gorm:begin_transaction", beginTransactionCallback)
+	DefaultCallback.Delete().Register("gorm:before_delete", beforeDeleteCallback)
+	DefaultCallback.Delete().Register("gorm:delete", deleteCallback)
+	DefaultCallback.Delete().Register("gorm:after_delete", afterDeleteCallback)
+	DefaultCallback.Delete().Register("gorm:commit_or_rollback_transaction", commitOrRollbackTransactionCallback)
 }
 
-func Delete(scope *Scope) {
+// beforeDeleteCallback will invoke `BeforeDelete` method before deleting
+func beforeDeleteCallback(scope *Scope) {
 	if !scope.HasError() {
+		scope.CallMethod("BeforeDelete")
+	}
+}
+
+// deleteCallback used to delete data from database or set deleted_at to current time (when using with soft delete)
+func deleteCallback(scope *Scope) {
+	if !scope.HasError() {
+		var extraOption string
+		if str, ok := scope.Get("gorm:delete_option"); ok {
+			extraOption = fmt.Sprint(str)
+		}
+
 		if !scope.Search.Unscoped && scope.HasColumn("DeletedAt") {
-			scope.Raw(
+			scope.Raw(fmt.Sprintf(
-				fmt.Sprintf("UPDATE %v SET deleted_at=%v %v",
+				"UPDATE %v SET deleted_at=%v%v%v",
 				scope.QuotedTableName(),
 				scope.AddToVars(NowFunc()),
-					scope.CombinedConditionSql(),
+				addExtraSpaceIfExist(scope.CombinedConditionSql()),
-				))
+				addExtraSpaceIfExist(extraOption),
+			)).Exec()
 		} else {
-			scope.Raw(fmt.Sprintf("DELETE FROM %v %v", scope.QuotedTableName(), scope.CombinedConditionSql()))
+			scope.Raw(fmt.Sprintf(
+				"DELETE FROM %v%v%v",
+				scope.QuotedTableName(),
+				addExtraSpaceIfExist(scope.CombinedConditionSql()),
+				addExtraSpaceIfExist(extraOption),
+			)).Exec()
 		}
-
-		scope.Exec()
 	}
 }
 
-func AfterDelete(scope *Scope) {
+// afterDeleteCallback will invoke `AfterDelete` method after deleting
-	scope.CallMethodWithErrorCheck("AfterDelete")
+func afterDeleteCallback(scope *Scope) {
+	if !scope.HasError() {
+		scope.CallMethod("AfterDelete")
 	}
-
-func init() {
-	DefaultCallback.Delete().Register("gorm:begin_transaction", BeginTransaction)
-	DefaultCallback.Delete().Register("gorm:before_delete", BeforeDelete)
-	DefaultCallback.Delete().Register("gorm:delete", Delete)
-	DefaultCallback.Delete().Register("gorm:after_delete", AfterDelete)
-	DefaultCallback.Delete().Register("gorm:commit_or_rollback_transaction", CommitOrRollbackTransaction)
 }

callback_query.go

@@ -6,115 +6,89 @@ import (
 	"reflect"
 )
 
-func Query(scope *Scope) {
+// Define callbacks for querying
-	defer scope.Trace(NowFunc())
+func init() {
+	DefaultCallback.Query().Register("gorm:query", queryCallback)
+	DefaultCallback.Query().Register("gorm:preload", preloadCallback)
+	DefaultCallback.Query().Register("gorm:after_query", afterQueryCallback)
+}
+
+// queryCallback used to query data from database
+func queryCallback(scope *Scope) {
+	defer scope.trace(NowFunc())
 
 	var (
 		isSlice    bool
 		isPtr      bool
-		anyRecordFound bool
+		results    = scope.IndirectValue()
-		destType       reflect.Type
+		resultType reflect.Type
 	)
 
 	if orderBy, ok := scope.Get("gorm:order_by_primary_key"); ok {
-		if primaryKey := scope.PrimaryKey(); primaryKey != "" {
+		if primaryField := scope.PrimaryField(); primaryField != nil {
-			scope.Search.Order(fmt.Sprintf("%v.%v %v", scope.QuotedTableName(), scope.Quote(primaryKey), orderBy))
+			scope.Search.Order(fmt.Sprintf("%v.%v %v", scope.QuotedTableName(), scope.Quote(primaryField.DBName), orderBy))
 		}
 	}
 
-	var dest = scope.IndirectValue()
 	if value, ok := scope.Get("gorm:query_destination"); ok {
-		dest = reflect.Indirect(reflect.ValueOf(value))
+		results = reflect.Indirect(reflect.ValueOf(value))
 	}
 
-	if kind := dest.Kind(); kind == reflect.Slice {
+	if kind := results.Kind(); kind == reflect.Slice {
 		isSlice = true
-		destType = dest.Type().Elem()
+		resultType = results.Type().Elem()
-		dest.Set(reflect.MakeSlice(dest.Type(), 0, 0))
+		results.Set(reflect.MakeSlice(results.Type(), 0, 0))
 
-		if destType.Kind() == reflect.Ptr {
+		if resultType.Kind() == reflect.Ptr {
 			isPtr = true
-			destType = destType.Elem()
+			resultType = resultType.Elem()
 		}
 	} else if kind != reflect.Struct {
 		scope.Err(errors.New("unsupported destination, should be slice or struct"))
 		return
 	}
 
-	scope.prepareQuerySql()
+	scope.prepareQuerySQL()
 
 	if !scope.HasError() {
-		rows, err := scope.SqlDB().Query(scope.Sql, scope.SqlVars...)
 		scope.db.RowsAffected = 0
-
+		if str, ok := scope.Get("gorm:query_option"); ok {
-		if scope.Err(err) != nil {
+			scope.SQL += addExtraSpaceIfExist(fmt.Sprint(str))
-			return
 		}
+
+		if rows, err := scope.SQLDB().Query(scope.SQL, scope.SQLVars...); scope.Err(err) == nil {
 			defer rows.Close()
 
 			columns, _ := rows.Columns()
 			for rows.Next() {
 				scope.db.RowsAffected++
 
-			anyRecordFound = true
+				elem := results
-			elem := dest
 				if isSlice {
-				elem = reflect.New(destType).Elem()
+					elem = reflect.New(resultType).Elem()
 				}
 
-			var values = make([]interface{}, len(columns))
+				scope.scan(rows, columns, scope.New(elem.Addr().Interface()).fieldsMap())
-
-			fields := scope.New(elem.Addr().Interface()).Fields()
-
-			for index, column := range columns {
-				if field, ok := fields[column]; ok {
-					if field.Field.Kind() == reflect.Ptr {
-						values[index] = field.Field.Addr().Interface()
-					} else {
-						reflectValue := reflect.New(reflect.PtrTo(field.Struct.Type))
-						reflectValue.Elem().Set(field.Field.Addr())
-						values[index] = reflectValue.Interface()
-					}
-				} else {
-					var value interface{}
-					values[index] = &value
-				}
-			}
-
-			scope.Err(rows.Scan(values...))
-
-			for index, column := range columns {
-				value := values[index]
-				if field, ok := fields[column]; ok {
-					if field.Field.Kind() == reflect.Ptr {
-						field.Field.Set(reflect.ValueOf(value).Elem())
-					} else if v := reflect.ValueOf(value).Elem().Elem(); v.IsValid() {
-						field.Field.Set(v)
-					}
-				}
-			}
 
 				if isSlice {
 					if isPtr {
-					dest.Set(reflect.Append(dest, elem.Addr()))
+						results.Set(reflect.Append(results, elem.Addr()))
 					} else {
-					dest.Set(reflect.Append(dest, elem))
+						results.Set(reflect.Append(results, elem))
 					}
 				}
 			}
 
-		if !anyRecordFound && !isSlice {
+			if scope.db.RowsAffected == 0 && !isSlice {
-			scope.Err(RecordNotFound)
+				scope.Err(ErrRecordNotFound)
+			}
 		}
 	}
 }
 
-func AfterQuery(scope *Scope) {
+// afterQueryCallback will invoke `AfterFind` method after querying
-	scope.CallMethodWithErrorCheck("AfterFind")
+func afterQueryCallback(scope *Scope) {
+	if !scope.HasError() {
+		scope.CallMethod("AfterFind")
 	}
-
-func init() {
-	DefaultCallback.Query().Register("gorm:query", Query)
-	DefaultCallback.Query().Register("gorm:preload", Preload)
-	DefaultCallback.Query().Register("gorm:after_query", AfterQuery)
 }

callback_query_preload.go

@@ -0,0 +1,308 @@
+package gorm
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+// preloadCallback used to preload associations
+func preloadCallback(scope *Scope) {
+	if scope.Search.preload == nil || scope.HasError() {
+		return
+	}
+
+	var (
+		preloadedMap = map[string]bool{}
+		fields       = scope.Fields()
+	)
+
+	for _, preload := range scope.Search.preload {
+		var (
+			preloadFields = strings.Split(preload.schema, ".")
+			currentScope  = scope
+			currentFields = fields
+		)
+
+		for idx, preloadField := range preloadFields {
+			var currentPreloadConditions []interface{}
+
+			// if not preloaded
+			if preloadKey := strings.Join(preloadFields[:idx+1], "."); !preloadedMap[preloadKey] {
+
+				// assign search conditions to last preload
+				if idx == len(preloadFields)-1 {
+					currentPreloadConditions = preload.conditions
+				}
+
+				for _, field := range currentFields {
+					if field.Name != preloadField || field.Relationship == nil {
+						continue
+					}
+
+					switch field.Relationship.Kind {
+					case "has_one":
+						currentScope.handleHasOnePreload(field, currentPreloadConditions)
+					case "has_many":
+						currentScope.handleHasManyPreload(field, currentPreloadConditions)
+					case "belongs_to":
+						currentScope.handleBelongsToPreload(field, currentPreloadConditions)
+					case "many_to_many":
+						currentScope.handleManyToManyPreload(field, currentPreloadConditions)
+					default:
+						scope.Err(errors.New("unsupported relation"))
+					}
+
+					preloadedMap[preloadKey] = true
+					break
+				}
+
+				if !preloadedMap[preloadKey] {
+					scope.Err(fmt.Errorf("can't preload field %s for %s", preloadField, currentScope.GetModelStruct().ModelType))
+					return
+				}
+			}
+
+			// preload next level
+			if idx < len(preloadFields)-1 {
+				currentScope = currentScope.getColumnAsScope(preloadField)
+				currentFields = currentScope.Fields()
+			}
+		}
+	}
+}
+
+func (scope *Scope) generatePreloadDBWithConditions(conditions []interface{}) (*DB, []interface{}) {
+	var (
+		preloadDB         = scope.NewDB()
+		preloadConditions []interface{}
+	)
+
+	for _, condition := range conditions {
+		if scopes, ok := condition.(func(*DB) *DB); ok {
+			preloadDB = scopes(preloadDB)
+		} else {
+			preloadConditions = append(preloadConditions, condition)
+		}
+	}
+
+	return preloadDB, preloadConditions
+}
+
+// handleHasOnePreload used to preload has one associations
+func (scope *Scope) handleHasOnePreload(field *Field, conditions []interface{}) {
+	relation := field.Relationship
+
+	// get relations's primary keys
+	primaryKeys := scope.getColumnAsArray(relation.AssociationForeignFieldNames, scope.Value)
+	if len(primaryKeys) == 0 {
+		return
+	}
+
+	// preload conditions
+	preloadDB, preloadConditions := scope.generatePreloadDBWithConditions(conditions)
+
+	// find relations
+	results := makeSlice(field.Struct.Type)
+	scope.Err(preloadDB.Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relation.ForeignDBNames), toQueryMarks(primaryKeys)), toQueryValues(primaryKeys)...).Find(results, preloadConditions...).Error)
+
+	// assign find results
+	var (
+		resultsValue       = indirect(reflect.ValueOf(results))
+		indirectScopeValue = scope.IndirectValue()
+	)
+
+	for i := 0; i < resultsValue.Len(); i++ {
+		result := resultsValue.Index(i)
+		if indirectScopeValue.Kind() == reflect.Slice {
+			foreignValues := getValueFromFields(result, relation.ForeignFieldNames)
+			for j := 0; j < indirectScopeValue.Len(); j++ {
+				if indirectValue := indirect(indirectScopeValue.Index(j)); equalAsString(getValueFromFields(indirectValue, relation.AssociationForeignFieldNames), foreignValues) {
+					indirectValue.FieldByName(field.Name).Set(result)
+					break
+				}
+			}
+		} else {
+			scope.Err(field.Set(result))
+		}
+	}
+}
+
+// handleHasManyPreload used to preload has many associations
+func (scope *Scope) handleHasManyPreload(field *Field, conditions []interface{}) {
+	relation := field.Relationship
+
+	// get relations's primary keys
+	primaryKeys := scope.getColumnAsArray(relation.AssociationForeignFieldNames, scope.Value)
+	if len(primaryKeys) == 0 {
+		return
+	}
+
+	// preload conditions
+	preloadDB, preloadConditions := scope.generatePreloadDBWithConditions(conditions)
+
+	// find relations
+	results := makeSlice(field.Struct.Type)
+	scope.Err(preloadDB.Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relation.ForeignDBNames), toQueryMarks(primaryKeys)), toQueryValues(primaryKeys)...).Find(results, preloadConditions...).Error)
+
+	// assign find results
+	var (
+		resultsValue       = indirect(reflect.ValueOf(results))
+		indirectScopeValue = scope.IndirectValue()
+	)
+
+	if indirectScopeValue.Kind() == reflect.Slice {
+		for i := 0; i < resultsValue.Len(); i++ {
+			result := resultsValue.Index(i)
+			foreignValues := getValueFromFields(result, relation.ForeignFieldNames)
+			for j := 0; j < indirectScopeValue.Len(); j++ {
+				object := indirect(indirectScopeValue.Index(j))
+				if equalAsString(getValueFromFields(object, relation.AssociationForeignFieldNames), foreignValues) {
+					objectField := object.FieldByName(field.Name)
+					objectField.Set(reflect.Append(objectField, result))
+					break
+				}
+			}
+		}
+	} else {
+		scope.Err(field.Set(resultsValue))
+	}
+}
+
+// handleBelongsToPreload used to preload belongs to associations
+func (scope *Scope) handleBelongsToPreload(field *Field, conditions []interface{}) {
+	relation := field.Relationship
+
+	// preload conditions
+	preloadDB, preloadConditions := scope.generatePreloadDBWithConditions(conditions)
+
+	// get relations's primary keys
+	primaryKeys := scope.getColumnAsArray(relation.ForeignFieldNames, scope.Value)
+	if len(primaryKeys) == 0 {
+		return
+	}
+
+	// find relations
+	results := makeSlice(field.Struct.Type)
+	scope.Err(preloadDB.Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relation.AssociationForeignDBNames), toQueryMarks(primaryKeys)), toQueryValues(primaryKeys)...).Find(results, preloadConditions...).Error)
+
+	// assign find results
+	var (
+		resultsValue       = indirect(reflect.ValueOf(results))
+		indirectScopeValue = scope.IndirectValue()
+	)
+
+	for i := 0; i < resultsValue.Len(); i++ {
+		result := resultsValue.Index(i)
+		if indirectScopeValue.Kind() == reflect.Slice {
+			value := getValueFromFields(result, relation.AssociationForeignFieldNames)
+			for j := 0; j < indirectScopeValue.Len(); j++ {
+				object := indirect(indirectScopeValue.Index(j))
+				if equalAsString(getValueFromFields(object, relation.ForeignFieldNames), value) {
+					object.FieldByName(field.Name).Set(result)
+				}
+			}
+		} else {
+			scope.Err(field.Set(result))
+		}
+	}
+}
+
+// handleManyToManyPreload used to preload many to many associations
+func (scope *Scope) handleManyToManyPreload(field *Field, conditions []interface{}) {
+	var (
+		relation         = field.Relationship
+		joinTableHandler = relation.JoinTableHandler
+		fieldType        = field.Struct.Type.Elem()
+		foreignKeyValue  interface{}
+		foreignKeyType   = reflect.ValueOf(&foreignKeyValue).Type()
+		linkHash         = map[string][]reflect.Value{}
+		isPtr            bool
+	)
+
+	if fieldType.Kind() == reflect.Ptr {
+		isPtr = true
+		fieldType = fieldType.Elem()
+	}
+
+	var sourceKeys = []string{}
+	for _, key := range joinTableHandler.SourceForeignKeys() {
+		sourceKeys = append(sourceKeys, key.DBName)
+	}
+
+	// preload conditions
+	preloadDB, preloadConditions := scope.generatePreloadDBWithConditions(conditions)
+
+	// generate query with join table
+	newScope := scope.New(reflect.New(fieldType).Interface())
+	preloadDB = preloadDB.Table(newScope.TableName()).Select("*")
+	preloadDB = joinTableHandler.JoinWith(joinTableHandler, preloadDB, scope.Value)
+
+	// preload inline conditions
+	if len(preloadConditions) > 0 {
+		preloadDB = preloadDB.Where(preloadConditions[0], preloadConditions[1:]...)
+	}
+
+	rows, err := preloadDB.Rows()
+
+	if scope.Err(err) != nil {
+		return
+	}
+	defer rows.Close()
+
+	columns, _ := rows.Columns()
+	for rows.Next() {
+		var (
+			elem   = reflect.New(fieldType).Elem()
+			fields = scope.New(elem.Addr().Interface()).fieldsMap()
+		)
+
+		// register foreign keys in join tables
+		for _, sourceKey := range sourceKeys {
+			fields[sourceKey] = &Field{Field: reflect.New(foreignKeyType).Elem()}
+		}
+
+		scope.scan(rows, columns, fields)
+
+		// generate hashed forkey keys in join table
+		var foreignKeys = make([]interface{}, len(sourceKeys))
+		for idx, sourceKey := range sourceKeys {
+			foreignKeys[idx] = fields[sourceKey].Field.Elem().Interface()
+		}
+		hashedSourceKeys := toString(foreignKeys)
+
+		if isPtr {
+			linkHash[hashedSourceKeys] = append(linkHash[hashedSourceKeys], elem.Addr())
+		} else {
+			linkHash[hashedSourceKeys] = append(linkHash[hashedSourceKeys], elem)
+		}
+	}
+
+	// assign find results
+	var (
+		indirectScopeValue = scope.IndirectValue()
+		fieldsSourceMap    = map[string]reflect.Value{}
+		foreignFieldNames  = []string{}
+		fields             = scope.fieldsMap()
+	)
+
+	for _, dbName := range relation.ForeignFieldNames {
+		if field, ok := fields[dbName]; ok {
+			foreignFieldNames = append(foreignFieldNames, field.Name)
+		}
+	}
+
+	if indirectScopeValue.Kind() == reflect.Slice {
+		for j := 0; j < indirectScopeValue.Len(); j++ {
+			object := indirect(indirectScopeValue.Index(j))
+			fieldsSourceMap[toString(getValueFromFields(object, foreignFieldNames))] = object.FieldByName(field.Name)
+		}
+	} else if indirectScopeValue.IsValid() {
+		fieldsSourceMap[toString(getValueFromFields(indirectScopeValue, foreignFieldNames))] = indirectScopeValue.FieldByName(field.Name)
+	}
+
+	for source, link := range linkHash {
+		fieldsSourceMap[source].Set(reflect.Append(fieldsSourceMap[source], link...))
+	}
+}

callback_save.go

@@ -2,15 +2,15 @@ package gorm
 
 import "reflect"
 
-func BeginTransaction(scope *Scope) {
+func beginTransactionCallback(scope *Scope) {
 	scope.Begin()
 }
 
-func CommitOrRollbackTransaction(scope *Scope) {
+func commitOrRollbackTransactionCallback(scope *Scope) {
 	scope.CommitOrRollback()
 }
 
-func SaveBeforeAssociations(scope *Scope) {
+func saveBeforeAssociationsCallback(scope *Scope) {
 	if !scope.shouldSaveAssociations() {
 		return
 	}
@@ -32,7 +32,7 @@ func SaveBeforeAssociations(scope *Scope) {
 	}
 }
 
-func SaveAfterAssociations(scope *Scope) {
+func saveAfterAssociationsCallback(scope *Scope) {
 	if !scope.shouldSaveAssociations() {
 		return
 	}

callback_test.go

@@ -23,7 +23,7 @@ func afterCreate1(s *Scope)  {}
 func afterCreate2(s *Scope)  {}
 
 func TestRegisterCallback(t *testing.T) {
-	var callback = &callback{processors: []*callbackProcessor{}}
+	var callback = &Callback{}
 
 	callback.Create().Register("before_create1", beforeCreate1)
 	callback.Create().Register("before_create2", beforeCreate2)
@@ -37,7 +37,7 @@ func TestRegisterCallback(t *testing.T) {
 }
 
 func TestRegisterCallbackWithOrder(t *testing.T) {
-	var callback1 = &callback{processors: []*callbackProcessor{}}
+	var callback1 = &Callback{}
 	callback1.Create().Register("before_create1", beforeCreate1)
 	callback1.Create().Register("create", create)
 	callback1.Create().Register("after_create1", afterCreate1)
@@ -46,7 +46,7 @@ func TestRegisterCallbackWithOrder(t *testing.T) {
 		t.Errorf("register callback with order")
 	}
 
-	var callback2 = &callback{processors: []*callbackProcessor{}}
+	var callback2 = &Callback{}
 
 	callback2.Update().Register("create", create)
 	callback2.Update().Before("create").Register("before_create1", beforeCreate1)
@@ -60,7 +60,7 @@ func TestRegisterCallbackWithOrder(t *testing.T) {
 }
 
 func TestRegisterCallbackWithComplexOrder(t *testing.T) {
-	var callback1 = &callback{processors: []*callbackProcessor{}}
+	var callback1 = &Callback{}
 
 	callback1.Query().Before("after_create1").After("before_create1").Register("create", create)
 	callback1.Query().Register("before_create1", beforeCreate1)
@@ -70,7 +70,7 @@ func TestRegisterCallbackWithComplexOrder(t *testing.T) {
 		t.Errorf("register callback with order")
 	}
 
-	var callback2 = &callback{processors: []*callbackProcessor{}}
+	var callback2 = &Callback{}
 
 	callback2.Delete().Before("after_create1").After("before_create1").Register("create", create)
 	callback2.Delete().Before("create").Register("before_create1", beforeCreate1)
@@ -86,7 +86,7 @@ func TestRegisterCallbackWithComplexOrder(t *testing.T) {
 func replaceCreate(s *Scope) {}
 
 func TestReplaceCallback(t *testing.T) {
-	var callback = &callback{processors: []*callbackProcessor{}}
+	var callback = &Callback{}
 
 	callback.Create().Before("after_create1").After("before_create1").Register("create", create)
 	callback.Create().Register("before_create1", beforeCreate1)
@@ -99,7 +99,7 @@ func TestReplaceCallback(t *testing.T) {
 }
 
 func TestRemoveCallback(t *testing.T) {
-	var callback = &callback{processors: []*callbackProcessor{}}
+	var callback = &Callback{}
 
 	callback.Create().Before("after_create1").After("before_create1").Register("create", create)
 	callback.Create().Register("before_create1", beforeCreate1)

callback_update.go

@@ -5,91 +5,102 @@ import (
 	"strings"
 )
 
-func AssignUpdateAttributes(scope *Scope) {
+// Define callbacks for updating
+func init() {
+	DefaultCallback.Update().Register("gorm:assign_updating_attributes", assignUpdatingAttributesCallback)
+	DefaultCallback.Update().Register("gorm:begin_transaction", beginTransactionCallback)
+	DefaultCallback.Update().Register("gorm:before_update", beforeUpdateCallback)
+	DefaultCallback.Update().Register("gorm:save_before_associations", saveBeforeAssociationsCallback)
+	DefaultCallback.Update().Register("gorm:update_time_stamp", updateTimeStampForUpdateCallback)
+	DefaultCallback.Update().Register("gorm:update", updateCallback)
+	DefaultCallback.Update().Register("gorm:save_after_associations", saveAfterAssociationsCallback)
+	DefaultCallback.Update().Register("gorm:after_update", afterUpdateCallback)
+	DefaultCallback.Update().Register("gorm:commit_or_rollback_transaction", commitOrRollbackTransactionCallback)
+}
+
+// assignUpdatingAttributesCallback assign updating attributes to model
+func assignUpdatingAttributesCallback(scope *Scope) {
 	if attrs, ok := scope.InstanceGet("gorm:update_interface"); ok {
 		if maps := convertInterfaceToMap(attrs); len(maps) > 0 {
-			protected, ok := scope.Get("gorm:ignore_protected_attrs")
+			if updateMaps, hasUpdate := scope.updatedAttrsWithValues(maps); hasUpdate {
-			_, updateColumn := scope.Get("gorm:update_column")
+				scope.InstanceSet("gorm:update_attrs", updateMaps)
-			updateAttrs, hasUpdate := scope.updatedAttrsWithValues(maps, ok && protected.(bool))
+			} else {
-
-			if updateColumn {
-				scope.InstanceSet("gorm:update_attrs", maps)
-			} else if len(updateAttrs) > 0 {
-				scope.InstanceSet("gorm:update_attrs", updateAttrs)
-			} else if !hasUpdate {
 				scope.SkipLeft()
-				return
 			}
 		}
 	}
 }
 
-func BeforeUpdate(scope *Scope) {
+// beforeUpdateCallback will invoke `BeforeSave`, `BeforeUpdate` method before updating
+func beforeUpdateCallback(scope *Scope) {
 	if _, ok := scope.Get("gorm:update_column"); !ok {
-		scope.CallMethodWithErrorCheck("BeforeSave")
+		if !scope.HasError() {
-		scope.CallMethodWithErrorCheck("BeforeUpdate")
+			scope.CallMethod("BeforeSave")
+		}
+		if !scope.HasError() {
+			scope.CallMethod("BeforeUpdate")
+		}
 	}
 }
 
-func UpdateTimeStampWhenUpdate(scope *Scope) {
+// updateTimeStampForUpdateCallback will set `UpdatedAt` when updating
+func updateTimeStampForUpdateCallback(scope *Scope) {
 	if _, ok := scope.Get("gorm:update_column"); !ok {
 		scope.SetColumn("UpdatedAt", NowFunc())
 	}
 }
 
-func Update(scope *Scope) {
+// updateCallback the callback used to update data to database
+func updateCallback(scope *Scope) {
 	if !scope.HasError() {
 		var sqls []string
 
 		if updateAttrs, ok := scope.InstanceGet("gorm:update_attrs"); ok {
-			for key, value := range updateAttrs.(map[string]interface{}) {
+			for column, value := range updateAttrs.(map[string]interface{}) {
-				if scope.changeableDBColumn(key) {
+				sqls = append(sqls, fmt.Sprintf("%v = %v", scope.Quote(column), scope.AddToVars(value)))
-					sqls = append(sqls, fmt.Sprintf("%v = %v", scope.Quote(key), scope.AddToVars(value)))
-				}
 			}
 		} else {
-			fields := scope.Fields()
+			for _, field := range scope.Fields() {
-			for _, field := range fields {
+				if scope.changeableField(field) {
-				if scope.changeableField(field) && !field.IsPrimaryKey && field.IsNormal {
+					if !field.IsPrimaryKey && field.IsNormal {
 						sqls = append(sqls, fmt.Sprintf("%v = %v", scope.Quote(field.DBName), scope.AddToVars(field.Field.Interface())))
 					} else if relationship := field.Relationship; relationship != nil && relationship.Kind == "belongs_to" {
-					for _, dbName := range relationship.ForeignDBNames {
+						for _, foreignKey := range relationship.ForeignDBNames {
-						if relationField := fields[dbName]; !scope.changeableField(relationField) && !relationField.IsBlank {
+							if foreignField, ok := scope.FieldByName(foreignKey); ok && !scope.changeableField(foreignField) {
-							sql := fmt.Sprintf("%v = %v", scope.Quote(relationField.DBName), scope.AddToVars(relationField.Field.Interface()))
+								sqls = append(sqls,
-							sqls = append(sqls, sql)
+									fmt.Sprintf("%v = %v", scope.Quote(foreignField.DBName), scope.AddToVars(foreignField.Field.Interface())))
 							}
 						}
 					}
 				}
 			}
+		}
+
+		var extraOption string
+		if str, ok := scope.Get("gorm:update_option"); ok {
+			extraOption = fmt.Sprint(str)
+		}
 
 		if len(sqls) > 0 {
 			scope.Raw(fmt.Sprintf(
-				"UPDATE %v SET %v %v",
+				"UPDATE %v SET %v%v%v",
 				scope.QuotedTableName(),
 				strings.Join(sqls, ", "),
-				scope.CombinedConditionSql(),
+				addExtraSpaceIfExist(scope.CombinedConditionSql()),
-			))
+				addExtraSpaceIfExist(extraOption),
-			scope.Exec()
+			)).Exec()
 		}
 	}
 }
 
-func AfterUpdate(scope *Scope) {
+// afterUpdateCallback will invoke `AfterUpdate`, `AfterSave` method after updating
+func afterUpdateCallback(scope *Scope) {
 	if _, ok := scope.Get("gorm:update_column"); !ok {
-		scope.CallMethodWithErrorCheck("AfterUpdate")
+		if !scope.HasError() {
-		scope.CallMethodWithErrorCheck("AfterSave")
+			scope.CallMethod("AfterUpdate")
+		}
+		if !scope.HasError() {
+			scope.CallMethod("AfterSave")
 		}
 	}
-
-func init() {
-	DefaultCallback.Update().Register("gorm:assign_update_attributes", AssignUpdateAttributes)
-	DefaultCallback.Update().Register("gorm:begin_transaction", BeginTransaction)
-	DefaultCallback.Update().Register("gorm:before_update", BeforeUpdate)
-	DefaultCallback.Update().Register("gorm:save_before_associations", SaveBeforeAssociations)
-	DefaultCallback.Update().Register("gorm:update_time_stamp_when_update", UpdateTimeStampWhenUpdate)
-	DefaultCallback.Update().Register("gorm:update", Update)
-	DefaultCallback.Update().Register("gorm:save_after_associations", SaveAfterAssociations)
-	DefaultCallback.Update().Register("gorm:after_update", AfterUpdate)
-	DefaultCallback.Update().Register("gorm:commit_or_rollback_transaction", CommitOrRollbackTransaction)
 }

common_dialect.go

@@ -1,117 +0,0 @@
-package gorm
-
-import (
-	"fmt"
-	"reflect"
-	"time"
-)
-
-type commonDialect struct{}
-
-func (commonDialect) BinVar(i int) string {
-	return "$$" // ?
-}
-
-func (commonDialect) SupportLastInsertId() bool {
-	return true
-}
-
-func (commonDialect) HasTop() bool {
-	return false
-}
-
-func (commonDialect) SqlTag(value reflect.Value, size int, autoIncrease bool) string {
-	switch value.Kind() {
-	case reflect.Bool:
-		return "BOOLEAN"
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
-		if autoIncrease {
-			return "INTEGER AUTO_INCREMENT"
-		}
-		return "INTEGER"
-	case reflect.Int64, reflect.Uint64:
-		if autoIncrease {
-			return "BIGINT AUTO_INCREMENT"
-		}
-		return "BIGINT"
-	case reflect.Float32, reflect.Float64:
-		return "FLOAT"
-	case reflect.String:
-		if size > 0 && size < 65532 {
-			return fmt.Sprintf("VARCHAR(%d)", size)
-		}
-		return "VARCHAR(65532)"
-	case reflect.Struct:
-		if _, ok := value.Interface().(time.Time); ok {
-			return "TIMESTAMP"
-		}
-	default:
-		if _, ok := value.Interface().([]byte); ok {
-			if size > 0 && size < 65532 {
-				return fmt.Sprintf("BINARY(%d)", size)
-			}
-			return "BINARY(65532)"
-		}
-	}
-	panic(fmt.Sprintf("invalid sql type %s (%s) for commonDialect", value.Type().Name(), value.Kind().String()))
-}
-
-func (commonDialect) ReturningStr(tableName, key string) string {
-	return ""
-}
-
-func (commonDialect) SelectFromDummyTable() string {
-	return ""
-}
-
-func (commonDialect) Quote(key string) string {
-	return fmt.Sprintf(`"%s"`, key)
-}
-
-func (c commonDialect) HasTable(scope *Scope, tableName string) bool {
-	var (
-		count        int
-		databaseName = c.CurrentDatabase(scope)
-	)
-	c.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.TABLES WHERE table_schema = ? AND table_name = ?", databaseName, tableName)
-	return count > 0
-}
-
-func (c commonDialect) HasColumn(scope *Scope, tableName string, columnName string) bool {
-	var (
-		count        int
-		databaseName = c.CurrentDatabase(scope)
-	)
-	c.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.COLUMNS WHERE table_schema = ? AND table_name = ? AND column_name = ?", databaseName, tableName, columnName)
-	return count > 0
-}
-
-func (c commonDialect) HasIndex(scope *Scope, tableName string, indexName string) bool {
-	var (
-		count        int
-		databaseName = c.CurrentDatabase(scope)
-	)
-	c.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.STATISTICS WHERE table_schema = ? AND table_name = ? AND index_name = ?", databaseName, tableName, indexName)
-	return count > 0
-}
-
-func (commonDialect) RemoveIndex(scope *Scope, indexName string) {
-	scope.Err(scope.NewDB().Exec(fmt.Sprintf("DROP INDEX %v ON %v", indexName, scope.QuotedTableName())).Error)
-}
-
-// RawScanInt scans the first column of the first row into the `scan' int pointer.
-// This function captures raw query errors and propagates them to the original scope.
-func (commonDialect) RawScanInt(scope *Scope, scanPtr *int, query string, args ...interface{}) {
-	scope.Err(scope.NewDB().Raw(query, args...).Row().Scan(scanPtr))
-}
-
-// RawScanString scans the first column of the first row into the `scan' string pointer.
-// This function captures raw query errors and propagates them to the original scope.
-func (commonDialect) RawScanString(scope *Scope, scanPtr *string, query string, args ...interface{}) {
-	scope.Err(scope.NewDB().Raw(query, args...).Row().Scan(scanPtr))
-}
-
-func (commonDialect) CurrentDatabase(scope *Scope) (name string) {
-	scope.Err(scope.NewDB().Raw("SELECT DATABASE()").Row().Scan(&name))
-	return
-}

customize_column_test.go

@@ -26,7 +26,7 @@ func TestCustomizeColumn(t *testing.T) {
 	DB.AutoMigrate(&CustomizeColumn{})
 
 	scope := DB.NewScope(&CustomizeColumn{})
-	if !scope.Dialect().HasColumn(scope, scope.TableName(), col) {
+	if !scope.Dialect().HasColumn(scope.TableName(), col) {
 		t.Errorf("CustomizeColumn should have column %s", col)
 	}
 

ddl_errors_test.go

@@ -17,8 +17,7 @@ func TestDdlErrors(t *testing.T) {
 		}
 	}()
 
-	DB.HasTable("foobarbaz")
+	if err := DB.Find(&User{}).Error; err == nil {
-	if DB.Error == nil {
 		t.Errorf("Expected operation on closed db to produce an error, but err was nil")
 	}
 }

delete_test.go

@@ -45,7 +45,7 @@ func TestSoftDelete(t *testing.T) {
 	type User struct {
 		Id        int64
 		Name      string
-		DeletedAt time.Time
+		DeletedAt *time.Time
 	}
 	DB.AutoMigrate(&User{})
 

dialect.go

@@ -1,41 +1,100 @@
 package gorm
 
 import (
+	"database/sql"
 	"fmt"
 	"reflect"
+	"strconv"
+	"strings"
 )
 
+// Dialect interface contains behaviors that differ across SQL database
 type Dialect interface {
-	BinVar(i int) string
+	// GetName get dialect's name
-	SupportLastInsertId() bool
+	GetName() string
-	HasTop() bool
+
-	SqlTag(value reflect.Value, size int, autoIncrease bool) string
+	// SetDB set db for dialect
-	ReturningStr(tableName, key string) string
+	SetDB(db *sql.DB)
-	SelectFromDummyTable() string
+
+	// BindVar return the placeholder for actual values in SQL statements, in many dbs it is "?", Postgres using $1
+	BindVar(i int) string
+	// Quote quotes field name to avoid SQL parsing exceptions by using a reserved word as a field name
 	Quote(key string) string
-	HasTable(scope *Scope, tableName string) bool
+	// DataTypeOf return data's sql type
-	HasColumn(scope *Scope, tableName string, columnName string) bool
+	DataTypeOf(field *StructField) string
-	HasIndex(scope *Scope, tableName string, indexName string) bool
+
-	RemoveIndex(scope *Scope, indexName string)
+	// HasIndex check has index or not
-	CurrentDatabase(scope *Scope) string
+	HasIndex(tableName string, indexName string) bool
+	// HasForeignKey check has foreign key or not
+	HasForeignKey(tableName string, foreignKeyName string) bool
+	// RemoveIndex remove index
+	RemoveIndex(tableName string, indexName string) error
+	// HasTable check has table or not
+	HasTable(tableName string) bool
+	// HasColumn check has column or not
+	HasColumn(tableName string, columnName string) bool
+
+	// LimitAndOffsetSQL return generated SQL with Limit and Offset, as mssql has special case
+	LimitAndOffsetSQL(limit, offset int) string
+	// SelectFromDummyTable return select values, for most dbs, `SELECT values` just works, mysql needs `SELECT value FROM DUAL`
+	SelectFromDummyTable() string
+	// LastInsertIdReturningSuffix most dbs support LastInsertId, but postgres needs to use `RETURNING`
+	LastInsertIDReturningSuffix(tableName, columnName string) string
 }
 
-func NewDialect(driver string) Dialect {
+var dialectsMap = map[string]Dialect{}
-	var d Dialect
+
-	switch driver {
+func newDialect(name string, db *sql.DB) Dialect {
-	case "postgres":
+	if value, ok := dialectsMap[name]; ok {
-		d = &postgres{}
+		dialect := reflect.New(reflect.TypeOf(value).Elem()).Interface().(Dialect)
-	case "foundation":
+		dialect.SetDB(db)
-		d = &foundation{}
+		return dialect
-	case "mysql":
-		d = &mysql{}
-	case "sqlite3":
-		d = &sqlite3{}
-	case "mssql":
-		d = &mssql{}
-	default:
-		fmt.Printf("`%v` is not officially supported, running under compatibility mode.\n", driver)
-		d = &commonDialect{}
 	}
-	return d
+
+	fmt.Printf("`%v` is not officially supported, running under compatibility mode.\n", name)
+	commontDialect := &commonDialect{}
+	commontDialect.SetDB(db)
+	return commontDialect
+}
+
+// RegisterDialect register new dialect
+func RegisterDialect(name string, dialect Dialect) {
+	dialectsMap[name] = dialect
+}
+
+// ParseFieldStructForDialect parse field struct for dialect
+func ParseFieldStructForDialect(field *StructField) (fieldValue reflect.Value, sqlType string, size int, additionalType string) {
+	// Get redirected field type
+	var reflectType = field.Struct.Type
+	for reflectType.Kind() == reflect.Ptr {
+		reflectType = reflectType.Elem()
+	}
+
+	// Get redirected field value
+	fieldValue = reflect.Indirect(reflect.New(reflectType))
+
+	// Get scanner's real value
+	var getScannerValue func(reflect.Value)
+	getScannerValue = func(value reflect.Value) {
+		fieldValue = value
+		if _, isScanner := reflect.New(fieldValue.Type()).Interface().(sql.Scanner); isScanner && fieldValue.Kind() == reflect.Struct {
+			getScannerValue(fieldValue.Field(0))
+		}
+	}
+	getScannerValue(fieldValue)
+
+	// Default Size
+	if num, ok := field.TagSettings["SIZE"]; ok {
+		size, _ = strconv.Atoi(num)
+	} else {
+		size = 255
+	}
+
+	// Default type from tag setting
+	additionalType = field.TagSettings["NOT NULL"] + " " + field.TagSettings["UNIQUE"]
+	if value, ok := field.TagSettings["DEFAULT"]; ok {
+		additionalType = additionalType + " DEFAULT " + value
+	}
+
+	return fieldValue, field.TagSettings["TYPE"], size, strings.TrimSpace(additionalType)
 }

dialect_common.go

@@ -0,0 +1,137 @@
+package gorm
+
+import (
+	"database/sql"
+	"fmt"
+	"reflect"
+	"strings"
+	"time"
+)
+
+type commonDialect struct {
+	db *sql.DB
+}
+
+func init() {
+	RegisterDialect("common", &commonDialect{})
+}
+
+func (commonDialect) GetName() string {
+	return "common"
+}
+
+func (s *commonDialect) SetDB(db *sql.DB) {
+	s.db = db
+}
+
+func (commonDialect) BindVar(i int) string {
+	return "$$" // ?
+}
+
+func (commonDialect) Quote(key string) string {
+	return fmt.Sprintf(`"%s"`, key)
+}
+
+func (commonDialect) DataTypeOf(field *StructField) string {
+	var dataValue, sqlType, size, additionalType = ParseFieldStructForDialect(field)
+
+	if sqlType == "" {
+		switch dataValue.Kind() {
+		case reflect.Bool:
+			sqlType = "BOOLEAN"
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok {
+				sqlType = "INTEGER AUTO_INCREMENT"
+			} else {
+				sqlType = "INTEGER"
+			}
+		case reflect.Int64, reflect.Uint64:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok {
+				sqlType = "BIGINT AUTO_INCREMENT"
+			} else {
+				sqlType = "BIGINT"
+			}
+		case reflect.Float32, reflect.Float64:
+			sqlType = "FLOAT"
+		case reflect.String:
+			if size > 0 && size < 65532 {
+				sqlType = fmt.Sprintf("VARCHAR(%d)", size)
+			} else {
+				sqlType = "VARCHAR(65532)"
+			}
+		case reflect.Struct:
+			if _, ok := dataValue.Interface().(time.Time); ok {
+				sqlType = "TIMESTAMP"
+			}
+		default:
+			if _, ok := dataValue.Interface().([]byte); ok {
+				if size > 0 && size < 65532 {
+					sqlType = fmt.Sprintf("BINARY(%d)", size)
+				} else {
+					sqlType = "BINARY(65532)"
+				}
+			}
+		}
+	}
+
+	if sqlType == "" {
+		panic(fmt.Sprintf("invalid sql type %s (%s) for commonDialect", dataValue.Type().Name(), dataValue.Kind().String()))
+	}
+
+	if strings.TrimSpace(additionalType) == "" {
+		return sqlType
+	}
+	return fmt.Sprintf("%v %v", sqlType, additionalType)
+}
+
+func (s commonDialect) HasIndex(tableName string, indexName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.STATISTICS WHERE table_schema = ? AND table_name = ? AND index_name = ?", s.currentDatabase(), tableName, indexName).Scan(&count)
+	return count > 0
+}
+
+func (s commonDialect) RemoveIndex(tableName string, indexName string) error {
+	_, err := s.db.Exec(fmt.Sprintf("DROP INDEX %v", indexName))
+	return err
+}
+
+func (s commonDialect) HasForeignKey(tableName string, foreignKeyName string) bool {
+	return false
+}
+
+func (s commonDialect) HasTable(tableName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.TABLES WHERE table_schema = ? AND table_name = ?", s.currentDatabase(), tableName).Scan(&count)
+	return count > 0
+}
+
+func (s commonDialect) HasColumn(tableName string, columnName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.COLUMNS WHERE table_schema = ? AND table_name = ? AND column_name = ?", s.currentDatabase(), tableName, columnName).Scan(&count)
+	return count > 0
+}
+
+func (s commonDialect) currentDatabase() (name string) {
+	s.db.QueryRow("SELECT DATABASE()").Scan(&name)
+	return
+}
+
+func (commonDialect) LimitAndOffsetSQL(limit, offset int) (sql string) {
+	if limit > 0 || offset > 0 {
+		if limit >= 0 {
+			sql += fmt.Sprintf(" LIMIT %d", limit)
+		}
+		if offset >= 0 {
+			sql += fmt.Sprintf(" OFFSET %d", offset)
+		}
+	}
+	return
+}
+
+func (commonDialect) SelectFromDummyTable() string {
+	return ""
+}
+
+func (commonDialect) LastInsertIDReturningSuffix(tableName, columnName string) string {
+	return ""
+}

dialect_mysql.go

@@ -0,0 +1,113 @@
+package gorm
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"time"
+)
+
+type mysql struct {
+	commonDialect
+}
+
+func init() {
+	RegisterDialect("mysql", &mysql{})
+}
+
+func (mysql) GetName() string {
+	return "mysql"
+}
+
+func (mysql) Quote(key string) string {
+	return fmt.Sprintf("`%s`", key)
+}
+
+// Get Data Type for MySQL Dialect
+func (mysql) DataTypeOf(field *StructField) string {
+	var dataValue, sqlType, size, additionalType = ParseFieldStructForDialect(field)
+
+	if sqlType == "" {
+		switch dataValue.Kind() {
+		case reflect.Bool:
+			sqlType = "boolean"
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				sqlType = "int AUTO_INCREMENT"
+			} else {
+				sqlType = "int"
+			}
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				sqlType = "int unsigned AUTO_INCREMENT"
+			} else {
+				sqlType = "int unsigned"
+			}
+		case reflect.Int64:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				sqlType = "bigint AUTO_INCREMENT"
+			} else {
+				sqlType = "bigint"
+			}
+		case reflect.Uint64:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				sqlType = "bigint unsigned AUTO_INCREMENT"
+			} else {
+				sqlType = "bigint unsigned"
+			}
+		case reflect.Float32, reflect.Float64:
+			sqlType = "double"
+		case reflect.String:
+			if size > 0 && size < 65532 {
+				sqlType = fmt.Sprintf("varchar(%d)", size)
+			} else {
+				sqlType = "longtext"
+			}
+		case reflect.Struct:
+			if _, ok := dataValue.Interface().(time.Time); ok {
+				if _, ok := field.TagSettings["NOT NULL"]; ok {
+					sqlType = "timestamp"
+				} else {
+					sqlType = "timestamp NULL"
+				}
+			}
+		default:
+			if _, ok := dataValue.Interface().([]byte); ok {
+				if size > 0 && size < 65532 {
+					sqlType = fmt.Sprintf("varbinary(%d)", size)
+				} else {
+					sqlType = "longblob"
+				}
+			}
+		}
+	}
+
+	if sqlType == "" {
+		panic(fmt.Sprintf("invalid sql type %s (%s) for mysql", dataValue.Type().Name(), dataValue.Kind().String()))
+	}
+
+	if strings.TrimSpace(additionalType) == "" {
+		return sqlType
+	}
+	return fmt.Sprintf("%v %v", sqlType, additionalType)
+}
+
+func (s mysql) RemoveIndex(tableName string, indexName string) error {
+	_, err := s.db.Exec(fmt.Sprintf("DROP INDEX %v ON %v", indexName, s.Quote(tableName)))
+	return err
+}
+
+func (s mysql) HasForeignKey(tableName string, foreignKeyName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS WHERE CONSTRAINT_SCHEMA=? AND TABLE_NAME=? AND CONSTRAINT_NAME=? AND CONSTRAINT_TYPE='FOREIGN KEY'", s.currentDatabase(), foreignKeyName).Scan(&count)
+	return count > 0
+}
+
+func (s mysql) currentDatabase() (name string) {
+	s.db.QueryRow("SELECT DATABASE()").Scan(&name)
+	return
+}
+
+func (mysql) SelectFromDummyTable() string {
+	return "FROM DUAL"
+}

dialect_postgres.go

@@ -0,0 +1,128 @@
+package gorm
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"time"
+)
+
+type postgres struct {
+	commonDialect
+}
+
+func init() {
+	RegisterDialect("postgres", &postgres{})
+}
+
+func (postgres) GetName() string {
+	return "postgres"
+}
+
+func (postgres) BindVar(i int) string {
+	return fmt.Sprintf("$%v", i)
+}
+
+func (postgres) DataTypeOf(field *StructField) string {
+	var dataValue, sqlType, size, additionalType = ParseFieldStructForDialect(field)
+
+	if sqlType == "" {
+		switch dataValue.Kind() {
+		case reflect.Bool:
+			sqlType = "boolean"
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				sqlType = "serial"
+			} else {
+				sqlType = "integer"
+			}
+		case reflect.Int64, reflect.Uint64:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				sqlType = "bigserial"
+			} else {
+				sqlType = "bigint"
+			}
+		case reflect.Float32, reflect.Float64:
+			sqlType = "numeric"
+		case reflect.String:
+			if size > 0 && size < 65532 {
+				sqlType = fmt.Sprintf("varchar(%d)", size)
+			} else {
+				sqlType = "text"
+			}
+		case reflect.Struct:
+			if _, ok := dataValue.Interface().(time.Time); ok {
+				sqlType = "timestamp with time zone"
+			}
+		case reflect.Map:
+			if dataValue.Type().Name() == "Hstore" {
+				sqlType = "hstore"
+			}
+		default:
+			if isByteArrayOrSlice(dataValue) {
+				sqlType = "bytea"
+			} else if isUUID(dataValue) {
+				sqlType = "uuid"
+			}
+		}
+	}
+
+	if sqlType == "" {
+		panic(fmt.Sprintf("invalid sql type %s (%s) for postgres", dataValue.Type().Name(), dataValue.Kind().String()))
+	}
+
+	if strings.TrimSpace(additionalType) == "" {
+		return sqlType
+	}
+	return fmt.Sprintf("%v %v", sqlType, additionalType)
+}
+
+func (s postgres) HasIndex(tableName string, indexName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM pg_indexes WHERE tablename = $1 AND indexname = $2", tableName, indexName).Scan(&count)
+	return count > 0
+}
+
+func (s postgres) HasForeignKey(tableName string, foreignKeyName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(con.conname) FROM pg_constraint con WHERE $1::regclass::oid = con.conrelid AND con.conname = $2 AND con.contype='f'", s.currentDatabase(), foreignKeyName).Scan(&count)
+	return count > 0
+}
+
+func (s postgres) HasTable(tableName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.tables WHERE table_name = $1 AND table_type = 'BASE TABLE'", tableName).Scan(&count)
+	return count > 0
+}
+
+func (s postgres) HasColumn(tableName string, columnName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.columns WHERE table_name = $1 AND column_name = $2", tableName, columnName).Scan(&count)
+	return count > 0
+}
+
+func (s postgres) currentDatabase() (name string) {
+	s.db.QueryRow("SELECT CURRENT_DATABASE()").Scan(&name)
+	return
+}
+
+func (s postgres) LastInsertIDReturningSuffix(tableName, key string) string {
+	return fmt.Sprintf("RETURNING %v.%v", tableName, key)
+}
+
+func (postgres) SupportLastInsertID() bool {
+	return false
+}
+
+func isByteArrayOrSlice(value reflect.Value) bool {
+	return (value.Kind() == reflect.Array || value.Kind() == reflect.Slice) && value.Type().Elem() == reflect.TypeOf(uint8(0))
+}
+
+func isUUID(value reflect.Value) bool {
+	if value.Kind() != reflect.Array || value.Type().Len() != 16 {
+		return false
+	}
+	typename := value.Type().Name()
+	lower := strings.ToLower(typename)
+	return "uuid" == lower || "guid" == lower
+}

dialect_sqlite3.go

@@ -0,0 +1,106 @@
+package gorm
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"time"
+)
+
+type sqlite3 struct {
+	commonDialect
+}
+
+func init() {
+	RegisterDialect("sqlite", &sqlite3{})
+	RegisterDialect("sqlite3", &sqlite3{})
+}
+
+func (sqlite3) GetName() string {
+	return "sqlite3"
+}
+
+// Get Data Type for Sqlite Dialect
+func (sqlite3) DataTypeOf(field *StructField) string {
+	var dataValue, sqlType, size, additionalType = ParseFieldStructForDialect(field)
+
+	if sqlType == "" {
+		switch dataValue.Kind() {
+		case reflect.Bool:
+			sqlType = "bool"
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
+			if field.IsPrimaryKey {
+				sqlType = "integer primary key autoincrement"
+			} else {
+				sqlType = "integer"
+			}
+		case reflect.Int64, reflect.Uint64:
+			if field.IsPrimaryKey {
+				sqlType = "integer primary key autoincrement"
+			} else {
+				sqlType = "bigint"
+			}
+		case reflect.Float32, reflect.Float64:
+			sqlType = "real"
+		case reflect.String:
+			if size > 0 && size < 65532 {
+				sqlType = fmt.Sprintf("varchar(%d)", size)
+			} else {
+				sqlType = "text"
+			}
+		case reflect.Struct:
+			if _, ok := dataValue.Interface().(time.Time); ok {
+				sqlType = "datetime"
+			}
+		default:
+			if _, ok := dataValue.Interface().([]byte); ok {
+				sqlType = "blob"
+			}
+		}
+	}
+
+	if sqlType == "" {
+		panic(fmt.Sprintf("invalid sql type %s (%s) for sqlite3", dataValue.Type().Name(), dataValue.Kind().String()))
+	}
+
+	if strings.TrimSpace(additionalType) == "" {
+		return sqlType
+	}
+	return fmt.Sprintf("%v %v", sqlType, additionalType)
+}
+
+func (s sqlite3) HasIndex(tableName string, indexName string) bool {
+	var count int
+	s.db.QueryRow(fmt.Sprintf("SELECT count(*) FROM sqlite_master WHERE tbl_name = ? AND sql LIKE '%%INDEX %v ON%%'", indexName), tableName).Scan(&count)
+	return count > 0
+}
+
+func (s sqlite3) HasTable(tableName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM sqlite_master WHERE type='table' AND name=?", tableName).Scan(&count)
+	return count > 0
+}
+
+func (s sqlite3) HasColumn(tableName string, columnName string) bool {
+	var count int
+	s.db.QueryRow(fmt.Sprintf("SELECT count(*) FROM sqlite_master WHERE tbl_name = ? AND (sql LIKE '%%\"%v\" %%' OR sql LIKE '%%%v %%');\n", columnName, columnName), tableName).Scan(&count)
+	return count > 0
+}
+
+func (s sqlite3) currentDatabase() (name string) {
+	var (
+		ifaces   = make([]interface{}, 3)
+		pointers = make([]*string, 3)
+		i        int
+	)
+	for i = 0; i < 3; i++ {
+		ifaces[i] = &pointers[i]
+	}
+	if err := s.db.QueryRow("PRAGMA database_list").Scan(ifaces...); err != nil {
+		return
+	}
+	if pointers[1] != nil {
+		name = *pointers[1]
+	}
+	return
+}

dialects/mssql/mssql.go

@@ -0,0 +1,150 @@
+package mssql
+
+import (
+	"database/sql"
+	"fmt"
+	"reflect"
+	"strings"
+	"time"
+
+	_ "github.com/denisenkom/go-mssqldb"
+	"github.com/jinzhu/gorm"
+)
+
+func setIdentityInsert(scope *gorm.Scope) {
+	if scope.Dialect().GetName() == "mssql" {
+		scope.NewDB().Exec(fmt.Sprintf("SET IDENTITY_INSERT %v ON", scope.TableName()))
+	}
+}
+
+func init() {
+	gorm.DefaultCallback.Create().After("gorm:begin_transaction").Register("mssql:set_identity_insert", setIdentityInsert)
+	gorm.RegisterDialect("mssql", &mssql{})
+}
+
+type mssql struct {
+	db *sql.DB
+}
+
+func (mssql) GetName() string {
+	return "mssql"
+}
+
+func (s *mssql) SetDB(db *sql.DB) {
+	s.db = db
+}
+
+func (mssql) BindVar(i int) string {
+	return "$$" // ?
+}
+
+func (mssql) Quote(key string) string {
+	return fmt.Sprintf(`"%s"`, key)
+}
+
+func (mssql) DataTypeOf(field *gorm.StructField) string {
+	var dataValue, sqlType, size, additionalType = gorm.ParseFieldStructForDialect(field)
+
+	if sqlType == "" {
+		switch dataValue.Kind() {
+		case reflect.Bool:
+			sqlType = "bit"
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				sqlType = "int IDENTITY(1,1)"
+			} else {
+				sqlType = "int"
+			}
+		case reflect.Int64, reflect.Uint64:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				sqlType = "bigint IDENTITY(1,1)"
+			} else {
+				sqlType = "bigint"
+			}
+		case reflect.Float32, reflect.Float64:
+			sqlType = "float"
+		case reflect.String:
+			if size > 0 && size < 65532 {
+				sqlType = fmt.Sprintf("nvarchar(%d)", size)
+			} else {
+				sqlType = "text"
+			}
+		case reflect.Struct:
+			if _, ok := dataValue.Interface().(time.Time); ok {
+				sqlType = "datetime2"
+			}
+		default:
+			if _, ok := dataValue.Interface().([]byte); ok {
+				if size > 0 && size < 65532 {
+					sqlType = fmt.Sprintf("varchar(%d)", size)
+				} else {
+					sqlType = "text"
+				}
+			}
+		}
+	}
+
+	if sqlType == "" {
+		panic(fmt.Sprintf("invalid sql type %s (%s) for mssql", dataValue.Type().Name(), dataValue.Kind().String()))
+	}
+
+	if strings.TrimSpace(additionalType) == "" {
+		return sqlType
+	}
+	return fmt.Sprintf("%v %v", sqlType, additionalType)
+}
+
+func (s mssql) HasIndex(tableName string, indexName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM sys.indexes WHERE name=? AND object_id=OBJECT_ID(?)", indexName, tableName).Scan(&count)
+	return count > 0
+}
+
+func (s mssql) RemoveIndex(tableName string, indexName string) error {
+	_, err := s.db.Exec(fmt.Sprintf("DROP INDEX %v ON %v", indexName, s.Quote(tableName)))
+	return err
+}
+
+func (s mssql) HasForeignKey(tableName string, foreignKeyName string) bool {
+	return false
+}
+
+func (s mssql) HasTable(tableName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.tables WHERE table_name = ? AND table_catalog = ?", tableName, s.currentDatabase()).Scan(&count)
+	return count > 0
+}
+
+func (s mssql) HasColumn(tableName string, columnName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM information_schema.columns WHERE table_catalog = ? AND table_name = ? AND column_name = ?", s.currentDatabase(), tableName, columnName).Scan(&count)
+	return count > 0
+}
+
+func (s mssql) currentDatabase() (name string) {
+	s.db.QueryRow("SELECT DB_NAME() AS [Current Database]").Scan(&name)
+	return
+}
+
+func (mssql) LimitAndOffsetSQL(limit, offset int) (sql string) {
+	if limit > 0 || offset > 0 {
+		if offset < 0 {
+			offset = 0
+		}
+
+		sql += fmt.Sprintf(" OFFSET %d ROWS", offset)
+
+		if limit >= 0 {
+			sql += fmt.Sprintf(" FETCH NEXT %d ROWS ONLY", limit)
+		}
+	}
+	return
+}
+
+func (mssql) SelectFromDummyTable() string {
+	return ""
+}
+
+func (mssql) LastInsertIDReturningSuffix(tableName, columnName string) string {
+	return ""
+}

dialects/mysql/mysql.go

@@ -0,0 +1,3 @@
+package mysql
+
+import _ "github.com/go-sql-driver/mysql"

dialects/postgres/postgres.go

@@ -0,0 +1,52 @@
+package postgres
+
+import (
+	"database/sql"
+	"database/sql/driver"
+
+	_ "github.com/lib/pq"
+	"github.com/lib/pq/hstore"
+)
+
+type Hstore map[string]*string
+
+func (h Hstore) Value() (driver.Value, error) {
+	hstore := hstore.Hstore{Map: map[string]sql.NullString{}}
+	if len(h) == 0 {
+		return nil, nil
+	}
+
+	for key, value := range h {
+		var s sql.NullString
+		if value != nil {
+			s.String = *value
+			s.Valid = true
+		}
+		hstore.Map[key] = s
+	}
+	return hstore.Value()
+}
+
+func (h *Hstore) Scan(value interface{}) error {
+	hstore := hstore.Hstore{}
+
+	if err := hstore.Scan(value); err != nil {
+		return err
+	}
+
+	if len(hstore.Map) == 0 {
+		return nil
+	}
+
+	*h = Hstore{}
+	for k := range hstore.Map {
+		if hstore.Map[k].Valid {
+			s := hstore.Map[k].String
+			(*h)[k] = &s
+		} else {
+			(*h)[k] = nil
+		}
+	}
+
+	return nil
+}

dialects/sqlite/sqlite.go

@@ -0,0 +1,3 @@
+package sqlite
+
+import _ "github.com/mattn/go-sqlite3"

doc/development.md

@@ -1,68 +0,0 @@
-# Gorm Development
-
-## Architecture
-
-The most notable component of Gorm is`gorm.DB`, which hold database connection. It could be initialized like this:
-
-    db, err := gorm.Open("postgres", "user=gorm dbname=gorm sslmode=disable")
-
-Gorm has chainable API, `gorm.DB` is the bridge of chains, it save related information and pass it to the next chain.
-
-Lets use below code to explain how it works:
-
-    db.Where("name = ?", "jinzhu").Find(&users)
-
-    // equivalent code
-    newdb := db.Where("name =?", "jinzhu")
-    newdb.Find(&user)
-
-`newdb` is `db`'s clone, in addition, it contains search conditions from the `Where` method.
-`Find` is a query method, it creates a `Scope` instance, and pass it as argument to query callbacks.
-
-There are four kinds of callbacks corresponds to sql's CURD: create callbacks, update callbacks, query callbacks, delete callbacks.
-
-## Callbacks
-
-### Register a new callback
-
-    func updateCreated(scope *Scope) {
-        if scope.HasColumn("Created") {
-            scope.SetColumn("Created", NowFunc())
-        }
-    }
-
-    db.Callback().Create().Register("update_created_at", updateCreated)
-    // register a callback for Create process
-
-### Delete an existing callback
-
-    db.Callback().Create().Remove("gorm:create")
-    // delete callback `gorm:create` from Create callbacks
-
-### Replace an existing callback
-
-    db.Callback().Create().Replace("gorm:create", newCreateFunction)
-    // replace callback `gorm:create` with new function `newCreateFunction` for Create process
-
-### Register callback orders
-
-    db.Callback().Create().Before("gorm:create").Register("update_created_at", updateCreated)
-    db.Callback().Create().After("gorm:create").Register("update_created_at", updateCreated)
-    db.Callback().Query().After("gorm:query").Register("my_plugin:after_query", afterQuery)
-    db.Callback().Delete().After("gorm:delete").Register("my_plugin:after_delete", afterDelete)
-    db.Callback().Update().Before("gorm:update").Register("my_plugin:before_update", beforeUpdate)
-    db.Callback().Create().Before("gorm:create").After("gorm:before_create").Register("my_plugin:before_create", beforeCreate)
-
-### Callback API
-
-Gorm is powered by callbacks, so you could refer below links to learn how to write callbacks
-
-[Create callbacks](https://github.com/jinzhu/gorm/blob/master/callback_create.go)
-
-[Update callbacks](https://github.com/jinzhu/gorm/blob/master/callback_update.go)
-
-[Query callbacks](https://github.com/jinzhu/gorm/blob/master/callback_query.go)
-
-[Delete callbacks](https://github.com/jinzhu/gorm/blob/master/callback_delete.go)
-
-View [https://github.com/jinzhu/gorm/blob/master/scope.go](https://github.com/jinzhu/gorm/blob/master/scope.go) for all available API

errors.go

@@ -6,25 +6,31 @@ import (
 )
 
 var (
-	RecordNotFound       = errors.New("record not found")
+	// ErrRecordNotFound record not found error, happens when haven't find any matched data when looking up with a struct
-	InvalidSql           = errors.New("invalid sql")
+	ErrRecordNotFound = errors.New("record not found")
-	NoNewAttrs           = errors.New("no new attributes")
+	// ErrInvalidSQL invalid SQL error, happens when you passed invalid SQL
-	NoValidTransaction   = errors.New("no valid transaction")
+	ErrInvalidSQL = errors.New("invalid SQL")
-	CantStartTransaction = errors.New("can't start transaction")
+	// ErrInvalidTransaction invalid transaction when you are trying to `Commit` or `Rollback`
+	ErrInvalidTransaction = errors.New("no valid transaction")
+	// ErrCantStartTransaction can't start transaction when you are trying to start one with `Begin`
+	ErrCantStartTransaction = errors.New("can't start transaction")
 )
 
 type errorsInterface interface {
 	GetErrors() []error
 }
 
+// Errors contains all happened errors
 type Errors struct {
 	errors []error
 }
 
+// GetErrors get all happened errors
 func (errs Errors) GetErrors() []error {
 	return errs.errors
 }
 
+// Add add an error
 func (errs *Errors) Add(err error) {
 	if errors, ok := err.(errorsInterface); ok {
 		for _, err := range errors.GetErrors() {
@@ -40,6 +46,7 @@ func (errs *Errors) Add(err error) {
 	}
 }
 
+// Error format happened errors
 func (errs Errors) Error() string {
 	var errors = []string{}
 	for _, e := range errs.errors {

field.go

@@ -7,12 +7,14 @@ import (
 	"reflect"
 )
 
+// Field model field definition
 type Field struct {
 	*StructField
 	IsBlank bool
 	Field   reflect.Value
 }
 
+// Set set a value to the field
 func (field *Field) Set(value interface{}) (err error) {
 	if !field.Field.IsValid() {
 		return errors.New("field value not valid")
@@ -56,35 +58,34 @@ func (field *Field) Set(value interface{}) (err error) {
 }
 
 // Fields get value's fields
-func (scope *Scope) Fields() map[string]*Field {
+func (scope *Scope) Fields() []*Field {
-	if scope.fields == nil {
+	var (
-		fields := map[string]*Field{}
+		fields             []*Field
-		modelStruct := scope.GetModelStruct()
+		indirectScopeValue = scope.IndirectValue()
+		isStruct           = indirectScopeValue.Kind() == reflect.Struct
+	)
 
-		indirectValue := scope.IndirectValue()
+	for _, structField := range scope.GetModelStruct().StructFields {
-		isStruct := indirectValue.Kind() == reflect.Struct
-		for _, structField := range modelStruct.StructFields {
-			if field, ok := fields[structField.DBName]; !ok || field.IsIgnored {
 		if isStruct {
-					fields[structField.DBName] = getField(indirectValue, structField)
+			fieldValue := indirectScopeValue
-				} else {
+			for _, name := range structField.Names {
-					fields[structField.DBName] = &Field{StructField: structField, IsBlank: true}
+				fieldValue = reflect.Indirect(fieldValue).FieldByName(name)
 			}
+			fields = append(fields, &Field{StructField: structField, Field: fieldValue, IsBlank: isBlank(fieldValue)})
+		} else {
+			fields = append(fields, &Field{StructField: structField, IsBlank: true})
 		}
 	}
 
-		scope.fields = fields
 	return fields
 }
-	return scope.fields
-}
 
-func getField(indirectValue reflect.Value, structField *StructField) *Field {
+func (scope *Scope) fieldsMap() map[string]*Field {
-	field := &Field{StructField: structField}
+	var results = map[string]*Field{}
-	for _, name := range structField.Names {
+	for _, field := range scope.Fields() {
-		indirectValue = reflect.Indirect(indirectValue).FieldByName(name)
+		if field.IsNormal {
+			results[field.DBName] = field
 		}
-	field.Field = indirectValue
+	}
-	field.IsBlank = isBlank(indirectValue)
+	return results
-	return field
 }

field_test.go

@@ -32,12 +32,16 @@ type CalculateFieldCategory struct {
 
 func TestCalculateField(t *testing.T) {
 	var field CalculateField
-	fields := DB.NewScope(&field).Fields()
+	var scope = DB.NewScope(&field)
-	if fields["children"].Relationship == nil || fields["category"].Relationship == nil {
+	if field, ok := scope.FieldByName("Children"); !ok || field.Relationship == nil {
 		t.Errorf("Should calculate fields correctly for the first time")
 	}
 
-	if field, ok := fields["embedded_name"]; !ok {
+	if field, ok := scope.FieldByName("Category"); !ok || field.Relationship == nil {
+		t.Errorf("Should calculate fields correctly for the first time")
+	}
+
+	if field, ok := scope.FieldByName("embedded_name"); !ok {
 		t.Errorf("should find embedded field")
 	} else if _, ok := field.TagSettings["NOT NULL"]; !ok {
 		t.Errorf("should find embedded field's tag settings")

foundation.go

@@ -1,83 +0,0 @@
-package gorm
-
-import (
-	"fmt"
-	"reflect"
-	"time"
-)
-
-type foundation struct {
-	commonDialect
-}
-
-func (foundation) BinVar(i int) string {
-	return fmt.Sprintf("$%v", i)
-}
-
-func (foundation) SupportLastInsertId() bool {
-	return false
-}
-
-func (foundation) SqlTag(value reflect.Value, size int, autoIncrease bool) string {
-	switch value.Kind() {
-	case reflect.Bool:
-		return "boolean"
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
-		if autoIncrease {
-			return "serial"
-		}
-		return "int"
-	case reflect.Int64, reflect.Uint64:
-		if autoIncrease {
-			return "bigserial"
-		}
-		return "bigint"
-	case reflect.Float32, reflect.Float64:
-		return "double"
-	case reflect.String:
-		if size > 0 && size < 65532 {
-			return fmt.Sprintf("varchar(%d)", size)
-		}
-		return "clob"
-	case reflect.Struct:
-		if _, ok := value.Interface().(time.Time); ok {
-			return "datetime"
-		}
-	default:
-		if _, ok := value.Interface().([]byte); ok {
-			return "blob"
-		}
-	}
-	panic(fmt.Sprintf("invalid sql type %s (%s) for foundation", value.Type().Name(), value.Kind().String()))
-}
-
-func (s foundation) ReturningStr(tableName, key string) string {
-	return fmt.Sprintf("RETURNING %v.%v", tableName, key)
-}
-
-func (s foundation) HasTable(scope *Scope, tableName string) bool {
-	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.tables WHERE table_schema = current_schema AND table_type = 'TABLE' AND table_name = ?", tableName)
-	return count > 0
-}
-
-func (s foundation) HasColumn(scope *Scope, tableName string, columnName string) bool {
-	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.columns WHERE table_schema = current_schema AND table_name = ? AND column_name = ?", tableName, columnName)
-	return count > 0
-}
-
-func (s foundation) RemoveIndex(scope *Scope, indexName string) {
-	scope.NewDB().Exec(fmt.Sprintf("DROP INDEX %v", s.Quote(indexName)))
-}
-
-func (s foundation) HasIndex(scope *Scope, tableName string, indexName string) bool {
-	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.indexes WHERE table_schema = current_schema AND table_name = ? AND index_name = ?", tableName, indexName)
-	return count > 0
-}
-
-func (s foundation) CurrentDatabase(scope *Scope) (name string) {
-	s.RawScanString(scope, &name, "SELECT CURRENT_SCHEMA")
-	return
-}

join_table_handler.go

@@ -7,40 +7,54 @@ import (
 	"strings"
 )
 
+// JoinTableHandlerInterface is an interface for how to handle many2many relations
 type JoinTableHandlerInterface interface {
+	// initialize join table handler
 	Setup(relationship *Relationship, tableName string, source reflect.Type, destination reflect.Type)
+	// Table return join table's table name
 	Table(db *DB) string
+	// Add create relationship in join table for source and destination
 	Add(handler JoinTableHandlerInterface, db *DB, source interface{}, destination interface{}) error
+	// Delete delete relationship in join table for sources
 	Delete(handler JoinTableHandlerInterface, db *DB, sources ...interface{}) error
+	// JoinWith query with `Join` conditions
 	JoinWith(handler JoinTableHandlerInterface, db *DB, source interface{}) *DB
+	// SourceForeignKeys return source foreign keys
 	SourceForeignKeys() []JoinTableForeignKey
+	// DestinationForeignKeys return destination foreign keys
 	DestinationForeignKeys() []JoinTableForeignKey
 }
 
+// JoinTableForeignKey join table foreign key struct
 type JoinTableForeignKey struct {
 	DBName            string
 	AssociationDBName string
 }
 
+// JoinTableSource is a struct that contains model type and foreign keys
 type JoinTableSource struct {
 	ModelType   reflect.Type
 	ForeignKeys []JoinTableForeignKey
 }
 
+// JoinTableHandler default join table handler
 type JoinTableHandler struct {
 	TableName   string          `sql:"-"`
 	Source      JoinTableSource `sql:"-"`
 	Destination JoinTableSource `sql:"-"`
 }
 
+// SourceForeignKeys return source foreign keys
 func (s *JoinTableHandler) SourceForeignKeys() []JoinTableForeignKey {
 	return s.Source.ForeignKeys
 }
 
+// DestinationForeignKeys return destination foreign keys
 func (s *JoinTableHandler) DestinationForeignKeys() []JoinTableForeignKey {
 	return s.Destination.ForeignKeys
 }
 
+// Setup initialize a default join table handler
 func (s *JoinTableHandler) Setup(relationship *Relationship, tableName string, source reflect.Type, destination reflect.Type) {
 	s.TableName = tableName
 
@@ -61,11 +75,12 @@ func (s *JoinTableHandler) Setup(relationship *Relationship, tableName string, s
 	}
 }
 
+// Table return join table's table name
 func (s JoinTableHandler) Table(db *DB) string {
 	return s.TableName
 }
 
-func (s JoinTableHandler) GetSearchMap(db *DB, sources ...interface{}) map[string]interface{} {
+func (s JoinTableHandler) getSearchMap(db *DB, sources ...interface{}) map[string]interface{} {
 	values := map[string]interface{}{}
 
 	for _, source := range sources {
@@ -74,20 +89,25 @@ func (s JoinTableHandler) GetSearchMap(db *DB, sources ...interface{}) map[strin
 
 		if s.Source.ModelType == modelType {
 			for _, foreignKey := range s.Source.ForeignKeys {
-				values[foreignKey.DBName] = scope.Fields()[foreignKey.AssociationDBName].Field.Interface()
+				if field, ok := scope.FieldByName(foreignKey.AssociationDBName); ok {
+					values[foreignKey.DBName] = field.Field.Interface()
+				}
 			}
 		} else if s.Destination.ModelType == modelType {
 			for _, foreignKey := range s.Destination.ForeignKeys {
-				values[foreignKey.DBName] = scope.Fields()[foreignKey.AssociationDBName].Field.Interface()
+				if field, ok := scope.FieldByName(foreignKey.AssociationDBName); ok {
+					values[foreignKey.DBName] = field.Field.Interface()
+				}
 			}
 		}
 	}
 	return values
 }
 
-func (s JoinTableHandler) Add(handler JoinTableHandlerInterface, db *DB, source1 interface{}, source2 interface{}) error {
+// Add create relationship in join table for source and destination
+func (s JoinTableHandler) Add(handler JoinTableHandlerInterface, db *DB, source interface{}, destination interface{}) error {
 	scope := db.NewScope("")
-	searchMap := s.GetSearchMap(db, source1, source2)
+	searchMap := s.getSearchMap(db, source, destination)
 
 	var assignColumns, binVars, conditions []string
 	var values []interface{}
@@ -116,6 +136,7 @@ func (s JoinTableHandler) Add(handler JoinTableHandlerInterface, db *DB, source1
 	return db.Exec(sql, values...).Error
 }
 
+// Delete delete relationship in join table for sources
 func (s JoinTableHandler) Delete(handler JoinTableHandlerInterface, db *DB, sources ...interface{}) error {
 	var (
 		scope      = db.NewScope(nil)
@@ -123,7 +144,7 @@ func (s JoinTableHandler) Delete(handler JoinTableHandlerInterface, db *DB, sour
 		values     []interface{}
 	)
 
-	for key, value := range s.GetSearchMap(db, sources...) {
+	for key, value := range s.getSearchMap(db, sources...) {
 		conditions = append(conditions, fmt.Sprintf("%v = ?", scope.Quote(key)))
 		values = append(values, value)
 	}
@@ -131,6 +152,7 @@ func (s JoinTableHandler) Delete(handler JoinTableHandlerInterface, db *DB, sour
 	return db.Table(handler.Table(db)).Where(strings.Join(conditions, " AND "), values...).Delete("").Error
 }
 
+// JoinWith query with `Join` conditions
 func (s JoinTableHandler) JoinWith(handler JoinTableHandlerInterface, db *DB, source interface{}) *DB {
 	var (
 		scope           = db.NewScope(source)
@@ -151,10 +173,12 @@ func (s JoinTableHandler) JoinWith(handler JoinTableHandlerInterface, db *DB, so
 
 		for _, foreignKey := range s.Source.ForeignKeys {
 			foreignDBNames = append(foreignDBNames, foreignKey.DBName)
-			foreignFieldNames = append(foreignFieldNames, scope.Fields()[foreignKey.AssociationDBName].Name)
+			if field, ok := scope.FieldByName(foreignKey.AssociationDBName); ok {
+				foreignFieldNames = append(foreignFieldNames, field.Name)
+			}
 		}
 
-		foreignFieldValues := scope.getColumnAsArray(foreignFieldNames)
+		foreignFieldValues := scope.getColumnAsArray(foreignFieldNames, scope.Value)
 
 		var condString string
 		if len(foreignFieldValues) > 0 {
@@ -165,7 +189,7 @@ func (s JoinTableHandler) JoinWith(handler JoinTableHandlerInterface, db *DB, so
 
 			condString = fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, quotedForeignDBNames), toQueryMarks(foreignFieldValues))
 
-			keys := scope.getColumnAsArray(foreignFieldNames)
+			keys := scope.getColumnAsArray(foreignFieldNames, scope.Value)
 			values = append(values, toQueryValues(keys))
 		} else {
 			condString = fmt.Sprintf("1 <> 1")
@@ -173,8 +197,8 @@ func (s JoinTableHandler) JoinWith(handler JoinTableHandlerInterface, db *DB, so
 
 		return db.Joins(fmt.Sprintf("INNER JOIN %v ON %v", quotedTableName, strings.Join(joinConditions, " AND "))).
 			Where(condString, toQueryValues(foreignFieldValues)...)
-	} else {
+	}
+
 	db.Error = errors.New("wrong source type for join table handler")
 	return db
 }
-}

join_table_test.go

@@ -18,7 +18,7 @@ type PersonAddress struct {
 	gorm.JoinTableHandler
 	PersonID  int
 	AddressID int
-	DeletedAt time.Time
+	DeletedAt *time.Time
 	CreatedAt time.Time
 }
 

logger.go

@@ -8,25 +8,28 @@ import (
 	"reflect"
 	"regexp"
 	"time"
+	"unicode"
+)
+
+var (
+	defaultLogger = Logger{log.New(os.Stdout, "\r\n", 0)}
+	sqlRegexp     = regexp.MustCompile(`(\$\d+)|\?`)
 )
 
 type logger interface {
 	Print(v ...interface{})
 }
 
-type LogWriter interface {
+type logWriter interface {
 	Println(v ...interface{})
 }
 
+// Logger default logger
 type Logger struct {
-	LogWriter
+	logWriter
 }
 
-var defaultLogger = Logger{log.New(os.Stdout, "\r\n", 0)}
+// Print format & print log
-
-// Format log
-var sqlRegexp = regexp.MustCompile(`(\$\d+)|\?`)
-
 func (logger Logger) Print(values ...interface{}) {
 	if len(values) > 1 {
 		level := values[0]
@@ -38,29 +41,44 @@ func (logger Logger) Print(values ...interface{}) {
 			// duration
 			messages = append(messages, fmt.Sprintf(" \033[36;1m[%.2fms]\033[0m ", float64(values[2].(time.Duration).Nanoseconds()/1e4)/100.0))
 			// sql
-			var formatedValues []interface{}
+			var sql string
+			var formattedValues []string
+
 			for _, value := range values[4].([]interface{}) {
 				indirectValue := reflect.Indirect(reflect.ValueOf(value))
 				if indirectValue.IsValid() {
 					value = indirectValue.Interface()
 					if t, ok := value.(time.Time); ok {
-						formatedValues = append(formatedValues, fmt.Sprintf("'%v'", t.Format(time.RFC3339)))
+						formattedValues = append(formattedValues, fmt.Sprintf("'%v'", t.Format(time.RFC3339)))
 					} else if b, ok := value.([]byte); ok {
-						formatedValues = append(formatedValues, fmt.Sprintf("'%v'", string(b)))
+						if str := string(b); isPrintable(str) {
+							formattedValues = append(formattedValues, fmt.Sprintf("'%v'", str))
+						} else {
+							formattedValues = append(formattedValues, "'<binary>'")
+						}
 					} else if r, ok := value.(driver.Valuer); ok {
 						if value, err := r.Value(); err == nil && value != nil {
-							formatedValues = append(formatedValues, fmt.Sprintf("'%v'", value))
+							formattedValues = append(formattedValues, fmt.Sprintf("'%v'", value))
 						} else {
-							formatedValues = append(formatedValues, "NULL")
+							formattedValues = append(formattedValues, "NULL")
 						}
 					} else {
-						formatedValues = append(formatedValues, fmt.Sprintf("'%v'", value))
+						formattedValues = append(formattedValues, fmt.Sprintf("'%v'", value))
 					}
 				} else {
-					formatedValues = append(formatedValues, fmt.Sprintf("'%v'", value))
+					formattedValues = append(formattedValues, fmt.Sprintf("'%v'", value))
 				}
 			}
-			messages = append(messages, fmt.Sprintf(sqlRegexp.ReplaceAllString(values[3].(string), "%v"), formatedValues...))
+
+			var formattedValuesLength = len(formattedValues)
+			for index, value := range sqlRegexp.Split(values[3].(string), -1) {
+				sql += value
+				if index < formattedValuesLength {
+					sql += formattedValues[index]
+				}
+			}
+
+			messages = append(messages, sql)
 		} else {
 			messages = append(messages, "\033[31;1m")
 			messages = append(messages, values[2:]...)
@@ -69,3 +87,12 @@ func (logger Logger) Print(values ...interface{}) {
 		logger.Println(messages...)
 	}
 }
+
+func isPrintable(s string) bool {
+	for _, r := range s {
+		if !unicode.IsPrint(r) {
+			return false
+		}
+	}
+	return true
+}

main.go

@@ -6,24 +6,14 @@ import (
 	"fmt"
 	"reflect"
 	"strings"
-	"time"
 )
 
-// NowFunc returns current time, this function is exported in order to be able
+// DB contains information for current db connection
-// to give the flexibility to the developer to customize it according to their
-// needs
-//
-//   e.g: return time.Now().UTC()
-//
-var NowFunc = func() time.Time {
-	return time.Now()
-}
-
 type DB struct {
 	Value             interface{}
 	Error             error
 	RowsAffected      int64
-	callback          *callback
+	callbacks         *Callback
 	db                sqlCommon
 	parent            *DB
 	search            *search
@@ -36,7 +26,18 @@ type DB struct {
 	joinTableHandlers map[string]JoinTableHandler
 }
 
-func Open(dialect string, args ...interface{}) (DB, error) {
+// Open initialize a new db connection, need to import driver first, e.g:
+//
+//     import _ "github.com/go-sql-driver/mysql"
+//     func main() {
+//       db, err := gorm.Open("mysql", "user:password@/dbname?charset=utf8&parseTime=True&loc=Local")
+//     }
+// GORM has wrapped some drivers, for easier to remember driver's import path, so you could import the mysql driver with
+//    import _ "github.com/jinzhu/gorm/dialects/mysql"
+//    // import _ "github.com/jinzhu/gorm/dialects/postgres"
+//    // import _ "github.com/jinzhu/gorm/dialects/sqlite"
+//    // import _ "github.com/jinzhu/gorm/dialects/mssql"
+func Open(dialect string, args ...interface{}) (*DB, error) {
 	var db DB
 	var err error
 
@@ -44,7 +45,7 @@ func Open(dialect string, args ...interface{}) (DB, error) {
 		err = errors.New("invalid database source")
 	} else {
 		var source string
-		var dbSql sqlCommon
+		var dbSQL sqlCommon
 
 		switch value := args[0].(type) {
 		case string:
@@ -55,22 +56,19 @@ func Open(dialect string, args ...interface{}) (DB, error) {
 				driver = value
 				source = args[1].(string)
 			}
-			if driver == "foundation" {
+			dbSQL, err = sql.Open(driver, source)
-				driver = "postgres" // FoundationDB speaks a postgres-compatible protocol.
-			}
-			dbSql, err = sql.Open(driver, source)
 		case sqlCommon:
 			source = reflect.Indirect(reflect.ValueOf(value)).FieldByName("dsn").String()
-			dbSql = value
+			dbSQL = value
 		}
 
 		db = DB{
-			dialect:  NewDialect(dialect),
+			dialect:   newDialect(dialect, dbSQL.(*sql.DB)),
 			logger:    defaultLogger,
-			callback: DefaultCallback,
+			callbacks: DefaultCallback,
 			source:    source,
 			values:    map[string]interface{}{},
-			db:       dbSql,
+			db:        dbSQL,
 		}
 		db.parent = &db
 
@@ -79,17 +77,20 @@ func Open(dialect string, args ...interface{}) (DB, error) {
 		}
 	}
 
-	return db, err
+	return &db, err
 }
 
+// Close close current db connection
 func (s *DB) Close() error {
 	return s.parent.db.(*sql.DB).Close()
 }
 
+// DB get `*sql.DB` from current connection
 func (s *DB) DB() *sql.DB {
 	return s.db.(*sql.DB)
 }
 
+// New clone a new db connection without search conditions
 func (s *DB) New() *DB {
 	clone := s.clone()
 	clone.search = nil
@@ -97,29 +98,32 @@ func (s *DB) New() *DB {
 	return clone
 }
 
-// NewScope create scope for callbacks, including DB's search information
+// NewScope create a scope for current operation
-func (db *DB) NewScope(value interface{}) *Scope {
+func (s *DB) NewScope(value interface{}) *Scope {
-	dbClone := db.clone()
+	dbClone := s.clone()
 	dbClone.Value = value
 	return &Scope{db: dbClone, Search: dbClone.search.clone(), Value: value}
 }
 
-// CommonDB Return the underlying sql.DB or sql.Tx instance.
+// CommonDB return the underlying `*sql.DB` or `*sql.Tx` instance, mainly intended to allow coexistence with legacy non-GORM code.
-// Use of this method is discouraged. It's mainly intended to allow
-// coexistence with legacy non-GORM code.
 func (s *DB) CommonDB() sqlCommon {
 	return s.db
 }
 
-func (s *DB) Callback() *callback {
+// Callback return `Callbacks` container, you could add/change/delete callbacks with it
-	s.parent.callback = s.parent.callback.clone()
+//     db.Callback().Create().Register("update_created_at", updateCreated)
-	return s.parent.callback
+// Refer https://jinzhu.github.io/gorm/development.html#callbacks
+func (s *DB) Callback() *Callback {
+	s.parent.callbacks = s.parent.callbacks.clone()
+	return s.parent.callbacks
 }
 
-func (s *DB) SetLogger(l logger) {
+// SetLogger replace default logger
-	s.logger = l
+func (s *DB) SetLogger(log logger) {
+	s.logger = log
 }
 
+// LogMode set log mode, `true` for detailed logs, `false` for no log, default, will only print error logs
 func (s *DB) LogMode(enable bool) *DB {
 	if enable {
 		s.logMode = 2
@@ -129,55 +133,82 @@ func (s *DB) LogMode(enable bool) *DB {
 	return s
 }
 
+// SingularTable use singular table by default
 func (s *DB) SingularTable(enable bool) {
 	modelStructsMap = newModelStructsMap()
 	s.parent.singularTable = enable
 }
 
+// Where return a new relation, filter records with given conditions, accepts `map`, `struct` or `string` as conditions, refer http://jinzhu.github.io/gorm/curd.html#query
 func (s *DB) Where(query interface{}, args ...interface{}) *DB {
 	return s.clone().search.Where(query, args...).db
 }
 
+// Or filter records that match before conditions or this one, similar to `Where`
 func (s *DB) Or(query interface{}, args ...interface{}) *DB {
 	return s.clone().search.Or(query, args...).db
 }
 
+// Not filter records that don't match current conditions, similar to `Where`
 func (s *DB) Not(query interface{}, args ...interface{}) *DB {
 	return s.clone().search.Not(query, args...).db
 }
 
-func (s *DB) Limit(value interface{}) *DB {
+// Limit specify the number of records to be retrieved
-	return s.clone().search.Limit(value).db
+func (s *DB) Limit(limit int) *DB {
+	return s.clone().search.Limit(limit).db
 }
 
-func (s *DB) Offset(value interface{}) *DB {
+// Offset specify the number of records to skip before starting to return the records
-	return s.clone().search.Offset(value).db
+func (s *DB) Offset(offset int) *DB {
+	return s.clone().search.Offset(offset).db
 }
 
+// Order specify order when retrieve records from database, set reorder to `true` to overwrite defined conditions
 func (s *DB) Order(value string, reorder ...bool) *DB {
 	return s.clone().search.Order(value, reorder...).db
 }
 
+// Select specify fields that you want to retrieve from database when querying, by default, will select all fields;
+// When creating/updating, specify fields that you want to save to database
 func (s *DB) Select(query interface{}, args ...interface{}) *DB {
 	return s.clone().search.Select(query, args...).db
 }
 
+// Omit specify fields that you want to ignore when saving to database for creating, updating
 func (s *DB) Omit(columns ...string) *DB {
 	return s.clone().search.Omit(columns...).db
 }
 
+// Group specify the group method on the find
 func (s *DB) Group(query string) *DB {
 	return s.clone().search.Group(query).db
 }
 
+// Having specify HAVING conditions for GROUP BY
 func (s *DB) Having(query string, values ...interface{}) *DB {
 	return s.clone().search.Having(query, values...).db
 }
 
-func (s *DB) Joins(query string) *DB {
+// Joins specify Joins conditions
-	return s.clone().search.Joins(query).db
+//     db.Joins("JOIN emails ON emails.user_id = users.id AND emails.email = ?", "jinzhu@example.org").Find(&user)
+func (s *DB) Joins(query string, args ...interface{}) *DB {
+	return s.clone().search.Joins(query, args...).db
 }
 
+// Scopes pass current database connection to arguments `func(*DB) *DB`, which could be used to add conditions dynamically
+//     func AmountGreaterThan1000(db *gorm.DB) *gorm.DB {
+//         return db.Where("amount > ?", 1000)
+//     }
+//
+//     func OrderStatus(status []string) func (db *gorm.DB) *gorm.DB {
+//         return func (db *gorm.DB) *gorm.DB {
+//             return db.Scopes(AmountGreaterThan1000).Where("status in (?)", status)
+//         }
+//     }
+//
+//     db.Scopes(AmountGreaterThan1000, OrderStatus([]string{"paid", "shipped"})).Find(&orders)
+// Refer https://jinzhu.github.io/gorm/curd.html#scopes
 func (s *DB) Scopes(funcs ...func(*DB) *DB) *DB {
 	for _, f := range funcs {
 		s = f(s)
@@ -185,60 +216,91 @@ func (s *DB) Scopes(funcs ...func(*DB) *DB) *DB {
 	return s
 }
 
+// Unscoped return all record including deleted record, refer Soft Delete https://jinzhu.github.io/gorm/curd.html#soft-delete
 func (s *DB) Unscoped() *DB {
 	return s.clone().search.unscoped().db
 }
 
+// Attrs initalize struct with argument if record not found with `FirstOrInit` https://jinzhu.github.io/gorm/curd.html#firstorinit or `FirstOrCreate` https://jinzhu.github.io/gorm/curd.html#firstorcreate
 func (s *DB) Attrs(attrs ...interface{}) *DB {
 	return s.clone().search.Attrs(attrs...).db
 }
 
+// Assign assign result with argument regardless it is found or not with `FirstOrInit` https://jinzhu.github.io/gorm/curd.html#firstorinit or `FirstOrCreate` https://jinzhu.github.io/gorm/curd.html#firstorcreate
 func (s *DB) Assign(attrs ...interface{}) *DB {
 	return s.clone().search.Assign(attrs...).db
 }
 
+// First find first record that match given conditions, order by primary key
 func (s *DB) First(out interface{}, where ...interface{}) *DB {
 	newScope := s.clone().NewScope(out)
 	newScope.Search.Limit(1)
 	return newScope.Set("gorm:order_by_primary_key", "ASC").
-		inlineCondition(where...).callCallbacks(s.parent.callback.queries).db
+		inlineCondition(where...).callCallbacks(s.parent.callbacks.queries).db
 }
 
+// Last find last record that match given conditions, order by primary key
 func (s *DB) Last(out interface{}, where ...interface{}) *DB {
 	newScope := s.clone().NewScope(out)
 	newScope.Search.Limit(1)
 	return newScope.Set("gorm:order_by_primary_key", "DESC").
-		inlineCondition(where...).callCallbacks(s.parent.callback.queries).db
+		inlineCondition(where...).callCallbacks(s.parent.callbacks.queries).db
 }
 
+// Find find records that match given conditions
 func (s *DB) Find(out interface{}, where ...interface{}) *DB {
-	return s.clone().NewScope(out).inlineCondition(where...).callCallbacks(s.parent.callback.queries).db
+	return s.clone().NewScope(out).inlineCondition(where...).callCallbacks(s.parent.callbacks.queries).db
 }
 
+// Scan scan value to a struct
 func (s *DB) Scan(dest interface{}) *DB {
-	return s.clone().NewScope(s.Value).Set("gorm:query_destination", dest).callCallbacks(s.parent.callback.queries).db
+	return s.clone().NewScope(s.Value).Set("gorm:query_destination", dest).callCallbacks(s.parent.callbacks.queries).db
 }
 
+// Row return `*sql.Row` with given conditions
 func (s *DB) Row() *sql.Row {
 	return s.NewScope(s.Value).row()
 }
 
+// Rows return `*sql.Rows` with given conditions
 func (s *DB) Rows() (*sql.Rows, error) {
 	return s.NewScope(s.Value).rows()
 }
 
+// ScanRows scan `*sql.Rows` to give struct
+func (s *DB) ScanRows(rows *sql.Rows, result interface{}) error {
+	var (
+		clone        = s.clone()
+		scope        = clone.NewScope(result)
+		columns, err = rows.Columns()
+	)
+
+	if clone.AddError(err) == nil {
+		scope.scan(rows, columns, scope.fieldsMap())
+	}
+
+	return clone.Error
+}
+
+// Pluck used to query single column from a model as a map
+//     var ages []int64
+//     db.Find(&users).Pluck("age", &ages)
 func (s *DB) Pluck(column string, value interface{}) *DB {
 	return s.NewScope(s.Value).pluck(column, value).db
 }
 
+// Count get how many records for a model
 func (s *DB) Count(value interface{}) *DB {
 	return s.NewScope(s.Value).count(value).db
 }
 
+// Related get related associations
 func (s *DB) Related(value interface{}, foreignKeys ...string) *DB {
 	return s.clone().NewScope(s.Value).related(value, foreignKeys...).db
 }
 
+// FirstOrInit find first matched record or initalize a new one with given conditions (only works with struct, map conditions)
+// https://jinzhu.github.io/gorm/curd.html#firstorinit
 func (s *DB) FirstOrInit(out interface{}, where ...interface{}) *DB {
 	c := s.clone()
 	if result := c.First(out, where...); result.Error != nil {
@@ -247,82 +309,100 @@ func (s *DB) FirstOrInit(out interface{}, where ...interface{}) *DB {
 		}
 		c.NewScope(out).inlineCondition(where...).initialize()
 	} else {
-		c.NewScope(out).updatedAttrsWithValues(convertInterfaceToMap(c.search.assignAttrs), false)
+		c.NewScope(out).updatedAttrsWithValues(convertInterfaceToMap(c.search.assignAttrs))
 	}
 	return c
 }
 
+// FirstOrCreate find first matched record or create a new one with given conditions (only works with struct, map conditions)
+// https://jinzhu.github.io/gorm/curd.html#firstorcreate
 func (s *DB) FirstOrCreate(out interface{}, where ...interface{}) *DB {
 	c := s.clone()
 	if result := c.First(out, where...); result.Error != nil {
 		if !result.RecordNotFound() {
 			return result
 		}
-		c.AddError(c.NewScope(out).inlineCondition(where...).initialize().callCallbacks(c.parent.callback.creates).db.Error)
+		c.AddError(c.NewScope(out).inlineCondition(where...).initialize().callCallbacks(c.parent.callbacks.creates).db.Error)
 	} else if len(c.search.assignAttrs) > 0 {
-		c.AddError(c.NewScope(out).InstanceSet("gorm:update_interface", c.search.assignAttrs).callCallbacks(c.parent.callback.updates).db.Error)
+		c.AddError(c.NewScope(out).InstanceSet("gorm:update_interface", c.search.assignAttrs).callCallbacks(c.parent.callbacks.updates).db.Error)
 	}
 	return c
 }
 
+// Update update attributes with callbacks, refer: https://jinzhu.github.io/gorm/curd.html#update
 func (s *DB) Update(attrs ...interface{}) *DB {
 	return s.Updates(toSearchableMap(attrs...), true)
 }
 
+// Updates update attributes with callbacks, refer: https://jinzhu.github.io/gorm/curd.html#update
 func (s *DB) Updates(values interface{}, ignoreProtectedAttrs ...bool) *DB {
 	return s.clone().NewScope(s.Value).
 		Set("gorm:ignore_protected_attrs", len(ignoreProtectedAttrs) > 0).
 		InstanceSet("gorm:update_interface", values).
-		callCallbacks(s.parent.callback.updates).db
+		callCallbacks(s.parent.callbacks.updates).db
 }
 
+// UpdateColumn update attributes without callbacks, refer: https://jinzhu.github.io/gorm/curd.html#update
 func (s *DB) UpdateColumn(attrs ...interface{}) *DB {
 	return s.UpdateColumns(toSearchableMap(attrs...))
 }
 
+// UpdateColumns update attributes without callbacks, refer: https://jinzhu.github.io/gorm/curd.html#update
 func (s *DB) UpdateColumns(values interface{}) *DB {
 	return s.clone().NewScope(s.Value).
 		Set("gorm:update_column", true).
 		Set("gorm:save_associations", false).
 		InstanceSet("gorm:update_interface", values).
-		callCallbacks(s.parent.callback.updates).db
+		callCallbacks(s.parent.callbacks.updates).db
 }
 
+// Save update value in database, if the value doesn't have primary key, will insert it
 func (s *DB) Save(value interface{}) *DB {
 	scope := s.clone().NewScope(value)
 	if scope.PrimaryKeyZero() {
-		return scope.callCallbacks(s.parent.callback.creates).db
+		return scope.callCallbacks(s.parent.callbacks.creates).db
 	}
-	return scope.callCallbacks(s.parent.callback.updates).db
+	return scope.callCallbacks(s.parent.callbacks.updates).db
 }
 
+// Create insert the value into database
 func (s *DB) Create(value interface{}) *DB {
 	scope := s.clone().NewScope(value)
-	return scope.callCallbacks(s.parent.callback.creates).db
+	return scope.callCallbacks(s.parent.callbacks.creates).db
 }
 
+// Delete delete value match given conditions, if the value has primary key, then will including the primary key as condition
 func (s *DB) Delete(value interface{}, where ...interface{}) *DB {
-	return s.clone().NewScope(value).inlineCondition(where...).callCallbacks(s.parent.callback.deletes).db
+	return s.clone().NewScope(value).inlineCondition(where...).callCallbacks(s.parent.callbacks.deletes).db
 }
 
+// Raw use raw sql as conditions, won't run it unless invoked by other methods
+//    db.Raw("SELECT name, age FROM users WHERE name = ?", 3).Scan(&result)
 func (s *DB) Raw(sql string, values ...interface{}) *DB {
 	return s.clone().search.Raw(true).Where(sql, values...).db
 }
 
+// Exec execute raw sql
 func (s *DB) Exec(sql string, values ...interface{}) *DB {
 	scope := s.clone().NewScope(nil)
-	generatedSql := scope.buildWhereCondition(map[string]interface{}{"query": sql, "args": values})
+	generatedSQL := scope.buildWhereCondition(map[string]interface{}{"query": sql, "args": values})
-	generatedSql = strings.TrimSuffix(strings.TrimPrefix(generatedSql, "("), ")")
+	generatedSQL = strings.TrimSuffix(strings.TrimPrefix(generatedSQL, "("), ")")
-	scope.Raw(generatedSql)
+	scope.Raw(generatedSQL)
 	return scope.Exec().db
 }
 
+// Model specify the model you would like to run db operations
+//    // update all users's name to `hello`
+//    db.Model(&User{}).Update("name", "hello")
+//    // if user's primary key is non-blank, will use it as condition, then will only update the user's name to `hello`
+//    db.Model(&user).Update("name", "hello")
 func (s *DB) Model(value interface{}) *DB {
 	c := s.clone()
 	c.Value = value
 	return c
 }
 
+// Table specify the table you would like to run db operations
 func (s *DB) Table(name string) *DB {
 	clone := s.clone()
 	clone.search.Table(name)
@@ -330,10 +410,12 @@ func (s *DB) Table(name string) *DB {
 	return clone
 }
 
+// Debug start debug mode
 func (s *DB) Debug() *DB {
 	return s.clone().LogMode(true)
 }
 
+// Begin begin a transaction
 func (s *DB) Begin() *DB {
 	c := s.clone()
 	if db, ok := c.db.(sqlDb); ok {
@@ -341,46 +423,56 @@ func (s *DB) Begin() *DB {
 		c.db = interface{}(tx).(sqlCommon)
 		c.AddError(err)
 	} else {
-		c.AddError(CantStartTransaction)
+		c.AddError(ErrCantStartTransaction)
 	}
 	return c
 }
 
+// Commit commit a transaction
 func (s *DB) Commit() *DB {
 	if db, ok := s.db.(sqlTx); ok {
 		s.AddError(db.Commit())
 	} else {
-		s.AddError(NoValidTransaction)
+		s.AddError(ErrInvalidTransaction)
 	}
 	return s
 }
 
+// Rollback rollback a transaction
 func (s *DB) Rollback() *DB {
 	if db, ok := s.db.(sqlTx); ok {
 		s.AddError(db.Rollback())
 	} else {
-		s.AddError(NoValidTransaction)
+		s.AddError(ErrInvalidTransaction)
 	}
 	return s
 }
 
+// NewRecord check if value's primary key is blank
 func (s *DB) NewRecord(value interface{}) bool {
 	return s.clone().NewScope(value).PrimaryKeyZero()
 }
 
+// RecordNotFound check if returning ErrRecordNotFound error
 func (s *DB) RecordNotFound() bool {
-	return s.Error == RecordNotFound
+	for _, err := range s.GetErrors() {
+		if err == ErrRecordNotFound {
+			return true
+		}
+	}
+	return false
 }
 
-// Migrations
+// CreateTable create table for models
-func (s *DB) CreateTable(values ...interface{}) *DB {
+func (s *DB) CreateTable(models ...interface{}) *DB {
 	db := s.clone()
-	for _, value := range values {
+	for _, model := range models {
-		db = db.NewScope(value).createTable().db
+		db = db.NewScope(model).createTable().db
 	}
 	return db
 }
 
+// DropTable drop table for models
 func (s *DB) DropTable(values ...interface{}) *DB {
 	db := s.clone()
 	for _, value := range values {
@@ -393,18 +485,18 @@ func (s *DB) DropTable(values ...interface{}) *DB {
 	return db
 }
 
+// DropTableIfExists drop table if it is exist
 func (s *DB) DropTableIfExists(values ...interface{}) *DB {
 	db := s.clone()
 	for _, value := range values {
-		if tableName, ok := value.(string); ok {
+		if s.HasTable(value) {
-			db = db.Table(tableName)
+			db.AddError(s.DropTable(value).Error)
 		}
-
-		db = db.NewScope(value).dropTableIfExists().db
 	}
 	return db
 }
 
+// HasTable check has table or not
 func (s *DB) HasTable(value interface{}) bool {
 	var (
 		scope     = s.clone().NewScope(value)
@@ -417,69 +509,64 @@ func (s *DB) HasTable(value interface{}) bool {
 		tableName = scope.TableName()
 	}
 
-	has := scope.Dialect().HasTable(scope, tableName)
+	has := scope.Dialect().HasTable(tableName)
 	s.AddError(scope.db.Error)
 	return has
 }
 
+// AutoMigrate run auto migration for given models, will only add missing fields, won't delete/change current data
 func (s *DB) AutoMigrate(values ...interface{}) *DB {
 	db := s.clone()
 	for _, value := range values {
-		db = db.NewScope(value).NeedPtr().autoMigrate().db
+		db = db.NewScope(value).autoMigrate().db
 	}
 	return db
 }
 
+// ModifyColumn modify column to type
 func (s *DB) ModifyColumn(column string, typ string) *DB {
 	scope := s.clone().NewScope(s.Value)
 	scope.modifyColumn(column, typ)
 	return scope.db
 }
 
+// DropColumn drop a column
 func (s *DB) DropColumn(column string) *DB {
 	scope := s.clone().NewScope(s.Value)
 	scope.dropColumn(column)
 	return scope.db
 }
 
-func (s *DB) AddIndex(indexName string, column ...string) *DB {
+// AddIndex add index for columns with given name
+func (s *DB) AddIndex(indexName string, columns ...string) *DB {
 	scope := s.Unscoped().NewScope(s.Value)
-	scope.addIndex(false, indexName, column...)
+	scope.addIndex(false, indexName, columns...)
 	return scope.db
 }
 
-func (s *DB) AddUniqueIndex(indexName string, column ...string) *DB {
+// AddUniqueIndex add unique index for columns with given name
+func (s *DB) AddUniqueIndex(indexName string, columns ...string) *DB {
 	scope := s.clone().NewScope(s.Value)
-	scope.addIndex(true, indexName, column...)
+	scope.addIndex(true, indexName, columns...)
 	return scope.db
 }
 
+// RemoveIndex remove index with name
 func (s *DB) RemoveIndex(indexName string) *DB {
 	scope := s.clone().NewScope(s.Value)
 	scope.removeIndex(indexName)
 	return scope.db
 }
 
-func (s *DB) CurrentDatabase() string {
+// AddForeignKey Add foreign key to the given scope, e.g:
-	var (
+//     db.Model(&User{}).AddForeignKey("city_id", "cities(id)", "RESTRICT", "RESTRICT")
-		scope = s.clone().NewScope(s.Value)
-		name  = s.dialect.CurrentDatabase(scope)
-	)
-	return name
-}
-
-/*
-Add foreign key to the given scope
-
-Example:
-	db.Model(&User{}).AddForeignKey("city_id", "cities(id)", "RESTRICT", "RESTRICT")
-*/
 func (s *DB) AddForeignKey(field string, dest string, onDelete string, onUpdate string) *DB {
 	scope := s.clone().NewScope(s.Value)
 	scope.addForeignKey(field, dest, onDelete, onUpdate)
 	return scope.db
 }
 
+// Association start `Association Mode` to handler relations things easir in that mode, refer: https://jinzhu.github.io/gorm/associations.html#association-mode
 func (s *DB) Association(column string) *Association {
 	var err error
 	scope := s.clone().NewScope(s.Value)
@@ -491,7 +578,7 @@ func (s *DB) Association(column string) *Association {
 			if field.Relationship == nil || len(field.Relationship.ForeignFieldNames) == 0 {
 				err = fmt.Errorf("invalid association %v for %v", column, scope.IndirectValue().Type())
 			} else {
-				return &Association{Scope: scope, Column: column, Field: field}
+				return &Association{scope: scope, column: column, field: field}
 			}
 		} else {
 			err = fmt.Errorf("%v doesn't have column %v", scope.IndirectValue().Type(), column)
@@ -501,26 +588,30 @@ func (s *DB) Association(column string) *Association {
 	return &Association{Error: err}
 }
 
+// Preload preload associations with given conditions
+//    db.Preload("Orders", "state NOT IN (?)", "cancelled").Find(&users)
 func (s *DB) Preload(column string, conditions ...interface{}) *DB {
 	return s.clone().search.Preload(column, conditions...).db
 }
 
-// Set set value by name
+// Set set setting by name, which could be used in callbacks, will clone a new db, and update its setting
 func (s *DB) Set(name string, value interface{}) *DB {
 	return s.clone().InstantSet(name, value)
 }
 
+// InstantSet instant set setting, will affect current db
 func (s *DB) InstantSet(name string, value interface{}) *DB {
 	s.values[name] = value
 	return s
 }
 
-// Get get value by name
+// Get get setting by name
 func (s *DB) Get(name string) (value interface{}, ok bool) {
 	value, ok = s.values[name]
 	return
 }
 
+// SetJoinTableHandler set a model's join table handler for a relation
 func (s *DB) SetJoinTableHandler(source interface{}, column string, handler JoinTableHandlerInterface) {
 	scope := s.NewScope(source)
 	for _, field := range scope.GetModelStruct().StructFields {
@@ -530,7 +621,7 @@ func (s *DB) SetJoinTableHandler(source interface{}, column string, handler Join
 				destination := (&Scope{Value: reflect.New(field.Struct.Type).Interface()}).GetModelStruct().ModelType
 				handler.Setup(field.Relationship, many2many, source, destination)
 				field.Relationship.JoinTableHandler = handler
-				if table := handler.Table(s); scope.Dialect().HasTable(scope, table) {
+				if table := handler.Table(s); scope.Dialect().HasTable(table) {
 					s.Table(table).AutoMigrate(handler)
 				}
 			}
@@ -538,9 +629,10 @@ func (s *DB) SetJoinTableHandler(source interface{}, column string, handler Join
 	}
 }
 
+// AddError add error to the db
 func (s *DB) AddError(err error) error {
 	if err != nil {
-		if err != RecordNotFound {
+		if err != ErrRecordNotFound {
 			if s.logMode == 0 {
 				go s.print(fileWithLineNum(), err)
 			} else {
@@ -559,6 +651,7 @@ func (s *DB) AddError(err error) error {
 	return err
 }
 
+// GetErrors get happened errors from the db
 func (s *DB) GetErrors() (errors []error) {
 	if errs, ok := s.Error.(errorsInterface); ok {
 		return errs.GetErrors()

main_private.go

@@ -10,7 +10,7 @@ func (s *DB) clone() *DB {
 	}
 
 	if s.search == nil {
-		db.search = &search{}
+		db.search = &search{limit: -1, offset: -1}
 	} else {
 		db.search = s.search.clone()
 	}

main_test.go

@@ -4,23 +4,23 @@ import (
 	"database/sql"
 	"database/sql/driver"
 	"fmt"
-	"strconv"
-
-	_ "github.com/denisenkom/go-mssqldb"
-	testdb "github.com/erikstmartin/go-testdb"
-	_ "github.com/go-sql-driver/mysql"
-	"github.com/jinzhu/gorm"
-	"github.com/jinzhu/now"
-	_ "github.com/lib/pq"
-	_ "github.com/mattn/go-sqlite3"
-
 	"os"
+	"reflect"
+	"strconv"
 	"testing"
 	"time"
+
+	"github.com/erikstmartin/go-testdb"
+	"github.com/jinzhu/gorm"
+	_ "github.com/jinzhu/gorm/dialects/mssql"
+	_ "github.com/jinzhu/gorm/dialects/mysql"
+	"github.com/jinzhu/gorm/dialects/postgres"
+	_ "github.com/jinzhu/gorm/dialects/sqlite"
+	"github.com/jinzhu/now"
 )
 
 var (
-	DB                 gorm.DB
+	DB                 *gorm.DB
 	t1, t2, t3, t4, t5 time.Time
 )
 
@@ -42,7 +42,7 @@ func init() {
 	runMigration()
 }
 
-func OpenTestConnection() (db gorm.DB, err error) {
+func OpenTestConnection() (db *gorm.DB, err error) {
 	switch os.Getenv("GORM_DIALECT") {
 	case "mysql":
 		// CREATE USER 'gorm'@'localhost' IDENTIFIED BY 'gorm';
@@ -115,7 +115,7 @@ func TestSetTable(t *testing.T) {
 	DB.Create(getPreparedUser("pluck_user3", "pluck_user"))
 
 	if err := DB.Table("users").Where("role = ?", "pluck_user").Pluck("age", &[]int{}).Error; err != nil {
-		t.Errorf("No errors should happen if set table for pluck", err.Error())
+		t.Error("No errors should happen if set table for pluck", err)
 	}
 
 	var users []User
@@ -376,7 +376,7 @@ func TestRows(t *testing.T) {
 
 	rows, err := DB.Table("users").Where("name = ? or name = ?", user2.Name, user3.Name).Select("name, age").Rows()
 	if err != nil {
-		t.Errorf("Not error should happen, but got")
+		t.Errorf("Not error should happen, got %v", err)
 	}
 
 	count := 0
@@ -386,8 +386,39 @@ func TestRows(t *testing.T) {
 		rows.Scan(&name, &age)
 		count++
 	}
+
 	if count != 2 {
-		t.Errorf("Should found two records with name 3")
+		t.Errorf("Should found two records")
+	}
+}
+
+func TestScanRows(t *testing.T) {
+	user1 := User{Name: "ScanRowsUser1", Age: 1, Birthday: now.MustParse("2000-1-1")}
+	user2 := User{Name: "ScanRowsUser2", Age: 10, Birthday: now.MustParse("2010-1-1")}
+	user3 := User{Name: "ScanRowsUser3", Age: 20, Birthday: now.MustParse("2020-1-1")}
+	DB.Save(&user1).Save(&user2).Save(&user3)
+
+	rows, err := DB.Table("users").Where("name = ? or name = ?", user2.Name, user3.Name).Select("name, age").Rows()
+	if err != nil {
+		t.Errorf("Not error should happen, got %v", err)
+	}
+
+	type Result struct {
+		Name string
+		Age  int
+	}
+
+	var results []Result
+	for rows.Next() {
+		var result Result
+		if err := DB.ScanRows(rows, &result); err != nil {
+			t.Errorf("should get no error, but got %v", err)
+		}
+		results = append(results, result)
+	}
+
+	if !reflect.DeepEqual(results, []Result{{Name: "ScanRowsUser2", Age: 10}, {Name: "ScanRowsUser3", Age: 20}}) {
+		t.Errorf("Should find expected results")
 	}
 }
 
@@ -448,7 +479,7 @@ func TestRaw(t *testing.T) {
 	}
 
 	DB.Exec("update users set name=? where name in (?)", "jinzhu", []string{user1.Name, user2.Name, user3.Name})
-	if DB.Where("name in (?)", []string{user1.Name, user2.Name, user3.Name}).First(&User{}).Error != gorm.RecordNotFound {
+	if DB.Where("name in (?)", []string{user1.Name, user2.Name, user3.Name}).First(&User{}).Error != gorm.ErrRecordNotFound {
 		t.Error("Raw sql to update records")
 	}
 }
@@ -470,14 +501,33 @@ func TestGroup(t *testing.T) {
 func TestJoins(t *testing.T) {
 	var user = User{
 		Name:       "joins",
+		CreditCard: CreditCard{Number: "411111111111"},
 		Emails:     []Email{{Email: "join1@example.com"}, {Email: "join2@example.com"}},
 	}
 	DB.Save(&user)
 
-	var result User
+	var users1 []User
-	DB.Joins("left join emails on emails.user_id = users.id").Where("name = ?", "joins").First(&result)
+	DB.Joins("left join emails on emails.user_id = users.id").Where("name = ?", "joins").Find(&users1)
-	if result.Name != "joins" || result.Id != user.Id {
+	if len(users1) != 2 {
-		t.Errorf("Should find all two emails with Join")
+		t.Errorf("should find two users using left join")
+	}
+
+	var users2 []User
+	DB.Joins("left join emails on emails.user_id = users.id AND emails.email = ?", "join1@example.com").Where("name = ?", "joins").First(&users2)
+	if len(users2) != 1 {
+		t.Errorf("should find one users using left join with conditions")
+	}
+
+	var users3 []User
+	DB.Joins("join emails on emails.user_id = users.id AND emails.email = ?", "join1@example.com").Joins("join credit_cards on credit_cards.user_id = users.id AND credit_cards.number = ?", "411111111111").Where("name = ?", "joins").First(&users3)
+	if len(users3) != 1 {
+		t.Errorf("should find one users using multiple left join conditions")
+	}
+
+	var users4 []User
+	DB.Joins("join emails on emails.user_id = users.id AND emails.email = ?", "join1@example.com").Joins("join credit_cards on credit_cards.user_id = users.id AND credit_cards.number = ?", "422222222222").Where("name = ?", "joins").First(&users4)
+	if len(users4) != 0 {
+		t.Errorf("should find no user when searching with unexisting credit card")
 	}
 }
 
@@ -557,7 +607,7 @@ func TestTimeWithZone(t *testing.T) {
 		DB.First(&findUser, "name = ?", name)
 		foundBirthday = findUser.Birthday.UTC().Format(format)
 		if foundBirthday != expectedBirthday {
-			t.Errorf("User's birthday should not be changed after find for name=%s, expected bday=%+v but actual value=%+v or %+v", name, expectedBirthday, foundBirthday)
+			t.Errorf("User's birthday should not be changed after find for name=%s, expected bday=%+v but actual value=%+v", name, expectedBirthday, foundBirthday)
 		}
 
 		if DB.Where("id = ? AND birthday >= ?", findUser.Id, user.Birthday.Add(-time.Minute)).First(&findUser2).RecordNotFound() {
@@ -573,7 +623,7 @@ func TestTimeWithZone(t *testing.T) {
 func TestHstore(t *testing.T) {
 	type Details struct {
 		Id   int64
-		Bulk gorm.Hstore
+		Bulk postgres.Hstore
 	}
 
 	if dialect := os.Getenv("GORM_DIALECT"); dialect != "postgres" {
@@ -659,7 +709,7 @@ func TestOpenExistingDB(t *testing.T) {
 	}
 
 	var user User
-	if db.Where("name = ?", "jnfeinstein").First(&user).Error == gorm.RecordNotFound {
+	if db.Where("name = ?", "jnfeinstein").First(&user).Error == gorm.ErrRecordNotFound {
 		t.Errorf("Should have found existing record")
 	}
 }

migration_test.go

@@ -31,7 +31,7 @@ func TestIndexes(t *testing.T) {
 	}
 
 	scope := DB.NewScope(&Email{})
-	if !scope.Dialect().HasIndex(scope, scope.TableName(), "idx_email_email") {
+	if !scope.Dialect().HasIndex(scope.TableName(), "idx_email_email") {
 		t.Errorf("Email should have index idx_email_email")
 	}
 
@@ -39,7 +39,7 @@ func TestIndexes(t *testing.T) {
 		t.Errorf("Got error when tried to remove index: %+v", err)
 	}
 
-	if scope.Dialect().HasIndex(scope, scope.TableName(), "idx_email_email") {
+	if scope.Dialect().HasIndex(scope.TableName(), "idx_email_email") {
 		t.Errorf("Email's index idx_email_email should be deleted")
 	}
 
@@ -47,7 +47,7 @@ func TestIndexes(t *testing.T) {
 		t.Errorf("Got error when tried to create index: %+v", err)
 	}
 
-	if !scope.Dialect().HasIndex(scope, scope.TableName(), "idx_email_email_and_user_id") {
+	if !scope.Dialect().HasIndex(scope.TableName(), "idx_email_email_and_user_id") {
 		t.Errorf("Email should have index idx_email_email_and_user_id")
 	}
 
@@ -55,7 +55,7 @@ func TestIndexes(t *testing.T) {
 		t.Errorf("Got error when tried to remove index: %+v", err)
 	}
 
-	if scope.Dialect().HasIndex(scope, scope.TableName(), "idx_email_email_and_user_id") {
+	if scope.Dialect().HasIndex(scope.TableName(), "idx_email_email_and_user_id") {
 		t.Errorf("Email's index idx_email_email_and_user_id should be deleted")
 	}
 
@@ -63,7 +63,7 @@ func TestIndexes(t *testing.T) {
 		t.Errorf("Got error when tried to create index: %+v", err)
 	}
 
-	if !scope.Dialect().HasIndex(scope, scope.TableName(), "idx_email_email_and_user_id") {
+	if !scope.Dialect().HasIndex(scope.TableName(), "idx_email_email_and_user_id") {
 		t.Errorf("Email should have index idx_email_email_and_user_id")
 	}
 
@@ -85,7 +85,7 @@ func TestIndexes(t *testing.T) {
 		t.Errorf("Got error when tried to remove index: %+v", err)
 	}
 
-	if scope.Dialect().HasIndex(scope, scope.TableName(), "idx_email_email_and_user_id") {
+	if scope.Dialect().HasIndex(scope.TableName(), "idx_email_email_and_user_id") {
 		t.Errorf("Email's index idx_email_email_and_user_id should be deleted")
 	}
 
@@ -117,11 +117,11 @@ func TestAutoMigration(t *testing.T) {
 	DB.Save(&BigEmail{Email: "jinzhu@example.org", UserAgent: "pc", RegisteredAt: time.Now()})
 
 	scope := DB.NewScope(&BigEmail{})
-	if !scope.Dialect().HasIndex(scope, scope.TableName(), "idx_email_agent") {
+	if !scope.Dialect().HasIndex(scope.TableName(), "idx_email_agent") {
 		t.Errorf("Failed to create index")
 	}
 
-	if !scope.Dialect().HasIndex(scope, scope.TableName(), "uix_emails_registered_at") {
+	if !scope.Dialect().HasIndex(scope.TableName(), "uix_emails_registered_at") {
 		t.Errorf("Failed to create index")
 	}
 

model.go

@@ -2,6 +2,10 @@ package gorm
 
 import "time"
 
+// Model base model definition, including fields `ID`, `CreatedAt`, `UpdatedAt`, `DeletedAt`, which could be embeded in your models
+//    type User struct {
+//      gorm.Model
+//    }
 type Model struct {
 	ID        uint `gorm:"primary_key"`
 	CreatedAt time.Time

model_struct.go

@@ -3,10 +3,8 @@ package gorm
 import (
 	"database/sql"
 	"errors"
-	"fmt"
 	"go/ast"
 	"reflect"
-	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -14,6 +12,7 @@ import (
 	"github.com/jinzhu/inflection"
 )
 
+// DefaultTableNameHandler default table name handler
 var DefaultTableNameHandler = func(db *DB, defaultTableName string) string {
 	return defaultTableName
 }
@@ -41,6 +40,7 @@ func newModelStructsMap() *safeModelStructsMap {
 
 var modelStructsMap = newModelStructsMap()
 
+// ModelStruct model definition
 type ModelStruct struct {
 	PrimaryFields    []*StructField
 	StructFields     []*StructField
@@ -48,10 +48,12 @@ type ModelStruct struct {
 	defaultTableName string
 }
 
+// TableName get model's table name
 func (s *ModelStruct) TableName(db *DB) string {
 	return DefaultTableNameHandler(db, s.defaultTableName)
 }
 
+// StructField model field's struct definition
 type StructField struct {
 	DBName          string
 	Name            string
@@ -107,7 +109,7 @@ func getForeignField(column string, fields []*StructField) *StructField {
 	return nil
 }
 
-// GetModelStruct generate model struct & relationships based on struct and tag definition
+// GetModelStruct get value's model struct, relationships based on struct and tag definition
 func (scope *Scope) GetModelStruct() *ModelStruct {
 	var modelStruct ModelStruct
 	// Scope value can't be nil
@@ -296,7 +298,10 @@ func (scope *Scope) GetModelStruct() *ModelStruct {
 										if len(associationForeignKeys) == 0 {
 											for _, foreignKey := range foreignKeys {
 												if strings.HasPrefix(foreignKey, associationType) {
-													associationForeignKeys = append(associationForeignKeys, strings.TrimPrefix(foreignKey, associationType))
+													associationForeignKey := strings.TrimPrefix(foreignKey, associationType)
+													if foreignField := getForeignField(associationForeignKey, modelStruct.StructFields); foreignField != nil {
+														associationForeignKeys = append(associationForeignKeys, associationForeignKey)
+													}
 												}
 											}
 											if len(associationForeignKeys) == 0 && len(foreignKeys) == 1 {
@@ -389,7 +394,10 @@ func (scope *Scope) GetModelStruct() *ModelStruct {
 									if len(associationForeignKeys) == 0 {
 										for _, foreignKey := range foreignKeys {
 											if strings.HasPrefix(foreignKey, associationType) {
-												associationForeignKeys = append(associationForeignKeys, strings.TrimPrefix(foreignKey, associationType))
+												associationForeignKey := strings.TrimPrefix(foreignKey, associationType)
+												if foreignField := getForeignField(associationForeignKey, modelStruct.StructFields); foreignField != nil {
+													associationForeignKeys = append(associationForeignKeys, associationForeignKey)
+												}
 											}
 										}
 										if len(associationForeignKeys) == 0 && len(foreignKeys) == 1 {
@@ -445,7 +453,10 @@ func (scope *Scope) GetModelStruct() *ModelStruct {
 									if len(associationForeignKeys) == 0 {
 										for _, foreignKey := range foreignKeys {
 											if strings.HasPrefix(foreignKey, field.Name) {
-												associationForeignKeys = append(associationForeignKeys, strings.TrimPrefix(foreignKey, field.Name))
+												associationForeignKey := strings.TrimPrefix(foreignKey, field.Name)
+												if foreignField := getForeignField(associationForeignKey, toFields); foreignField != nil {
+													associationForeignKeys = append(associationForeignKeys, associationForeignKey)
+												}
 											}
 										}
 										if len(associationForeignKeys) == 0 && len(foreignKeys) == 1 {
@@ -508,63 +519,11 @@ func (scope *Scope) GetModelStruct() *ModelStruct {
 	return &modelStruct
 }
 
+// GetStructFields get model's field structs
 func (scope *Scope) GetStructFields() (fields []*StructField) {
 	return scope.GetModelStruct().StructFields
 }
 
-func (scope *Scope) generateSqlTag(field *StructField) string {
-	var sqlType string
-	structType := field.Struct.Type
-	if structType.Kind() == reflect.Ptr {
-		structType = structType.Elem()
-	}
-	reflectValue := reflect.Indirect(reflect.New(structType))
-
-	if value, ok := field.TagSettings["TYPE"]; ok {
-		sqlType = value
-	}
-
-	additionalType := field.TagSettings["NOT NULL"] + " " + field.TagSettings["UNIQUE"]
-	if value, ok := field.TagSettings["DEFAULT"]; ok {
-		additionalType = additionalType + " DEFAULT " + value
-	}
-
-	if field.IsScanner {
-		var getScannerValue func(reflect.Value)
-		getScannerValue = func(value reflect.Value) {
-			reflectValue = value
-			if _, isScanner := reflect.New(reflectValue.Type()).Interface().(sql.Scanner); isScanner && reflectValue.Kind() == reflect.Struct {
-				getScannerValue(reflectValue.Field(0))
-			}
-		}
-		getScannerValue(reflectValue)
-	}
-
-	if sqlType == "" {
-		var size = 255
-
-		if value, ok := field.TagSettings["SIZE"]; ok {
-			size, _ = strconv.Atoi(value)
-		}
-
-		v, autoIncrease := field.TagSettings["AUTO_INCREMENT"]
-		if field.IsPrimaryKey {
-			autoIncrease = true
-		}
-		if v == "FALSE" {
-			autoIncrease = false
-		}
-
-		sqlType = scope.Dialect().SqlTag(reflectValue, size, autoIncrease)
-	}
-
-	if strings.TrimSpace(additionalType) == "" {
-		return sqlType
-	} else {
-		return fmt.Sprintf("%v %v", sqlType, additionalType)
-	}
-}
-
 func parseTagSetting(tags reflect.StructTag) map[string]string {
 	setting := map[string]string{}
 	for _, str := range []string{tags.Get("sql"), tags.Get("gorm")} {

mssql.go

@@ -1,80 +0,0 @@
-package gorm
-
-import (
-	"fmt"
-	"reflect"
-	"time"
-)
-
-type mssql struct {
-	commonDialect
-}
-
-func (mssql) HasTop() bool {
-	return true
-}
-
-func (mssql) SqlTag(value reflect.Value, size int, autoIncrease bool) string {
-	switch value.Kind() {
-	case reflect.Bool:
-		return "bit"
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
-		if autoIncrease {
-			return "int IDENTITY(1,1)"
-		}
-		return "int"
-	case reflect.Int64, reflect.Uint64:
-		if autoIncrease {
-			return "bigint IDENTITY(1,1)"
-		}
-		return "bigint"
-	case reflect.Float32, reflect.Float64:
-		return "float"
-	case reflect.String:
-		if size > 0 && size < 65532 {
-			return fmt.Sprintf("nvarchar(%d)", size)
-		}
-		return "text"
-	case reflect.Struct:
-		if _, ok := value.Interface().(time.Time); ok {
-			return "datetime2"
-		}
-	default:
-		if _, ok := value.Interface().([]byte); ok {
-			if size > 0 && size < 65532 {
-				return fmt.Sprintf("varchar(%d)", size)
-			}
-			return "text"
-		}
-	}
-	panic(fmt.Sprintf("invalid sql type %s (%s) for mssql", value.Type().Name(), value.Kind().String()))
-}
-
-func (s mssql) HasTable(scope *Scope, tableName string) bool {
-	var (
-		count        int
-		databaseName = s.CurrentDatabase(scope)
-	)
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.tables WHERE table_name = ? AND table_catalog = ?", tableName, databaseName)
-	return count > 0
-}
-
-func (s mssql) HasColumn(scope *Scope, tableName string, columnName string) bool {
-	var (
-		count        int
-		databaseName = s.CurrentDatabase(scope)
-	)
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM information_schema.columns WHERE table_catalog = ? AND table_name = ? AND column_name = ?", databaseName, tableName, columnName)
-	return count > 0
-}
-
-func (s mssql) HasIndex(scope *Scope, tableName string, indexName string) bool {
-	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM sys.indexes WHERE name=? AND object_id=OBJECT_ID(?)", indexName, tableName)
-	return count > 0
-}
-
-func (s mssql) CurrentDatabase(scope *Scope) (name string) {
-	s.RawScanString(scope, &name, "SELECT DB_NAME() AS [Current Database]")
-	return
-}

multi_primary_keys_test.go

@@ -21,7 +21,7 @@ type Tag struct {
 	ID     uint   `gorm:"primary_key"`
 	Locale string `gorm:"primary_key"`
 	Value  string
-	Blogs  []*Blog `gorm:"many2many:"blogs_tags`
+	Blogs  []*Blog `gorm:"many2many:blogs_tags"`
 }
 
 func compareTags(tags []Tag, contents []string) bool {

mysql.go

@@ -1,70 +0,0 @@
-package gorm
-
-import (
-	"fmt"
-	"reflect"
-	"time"
-)
-
-type mysql struct {
-	commonDialect
-}
-
-func (mysql) SqlTag(value reflect.Value, size int, autoIncrease bool) string {
-	switch value.Kind() {
-	case reflect.Bool:
-		return "boolean"
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32:
-		if autoIncrease {
-			return "int AUTO_INCREMENT"
-		}
-		return "int"
-	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
-		if autoIncrease {
-			return "int unsigned AUTO_INCREMENT"
-		}
-		return "int unsigned"
-	case reflect.Int64:
-		if autoIncrease {
-			return "bigint AUTO_INCREMENT"
-		}
-		return "bigint"
-	case reflect.Uint64:
-		if autoIncrease {
-			return "bigint unsigned AUTO_INCREMENT"
-		}
-		return "bigint unsigned"
-	case reflect.Float32, reflect.Float64:
-		return "double"
-	case reflect.String:
-		if size > 0 && size < 65532 {
-			return fmt.Sprintf("varchar(%d)", size)
-		}
-		return "longtext"
-	case reflect.Struct:
-		if _, ok := value.Interface().(time.Time); ok {
-			return "timestamp NULL"
-		}
-	default:
-		if _, ok := value.Interface().([]byte); ok {
-			if size > 0 && size < 65532 {
-				return fmt.Sprintf("varbinary(%d)", size)
-			}
-			return "longblob"
-		}
-	}
-	panic(fmt.Sprintf("invalid sql type %s (%s) for mysql", value.Type().Name(), value.Kind().String()))
-}
-
-func (mysql) Quote(key string) string {
-	return fmt.Sprintf("`%s`", key)
-}
-
-func (mysql) SelectFromDummyTable() string {
-	return "FROM DUAL"
-}
-
-func (s mysql) CurrentDatabase(scope *Scope) (name string) {
-	s.RawScanString(scope, &name, "SELECT DATABASE()")
-	return
-}

pointer_test.go

@@ -39,46 +39,46 @@ func TestPointerFields(t *testing.T) {
 
 	var nilPointerStruct = PointerStruct{}
 	if err := DB.Create(&nilPointerStruct).Error; err != nil {
-		t.Errorf("Failed to save nil pointer struct", err)
+		t.Error("Failed to save nil pointer struct", err)
 	}
 
 	var pointerStruct2 PointerStruct
 	if err := DB.First(&pointerStruct2, "id = ?", nilPointerStruct.ID).Error; err != nil {
-		t.Errorf("Failed to query saved nil pointer struct", err)
+		t.Error("Failed to query saved nil pointer struct", err)
 	}
 
 	var normalStruct2 NormalStruct
 	if err := DB.Table(tableName).First(&normalStruct2, "id = ?", nilPointerStruct.ID).Error; err != nil {
-		t.Errorf("Failed to query saved nil pointer struct", err)
+		t.Error("Failed to query saved nil pointer struct", err)
 	}
 
 	var partialNilPointerStruct1 = PointerStruct{Num: &num}
 	if err := DB.Create(&partialNilPointerStruct1).Error; err != nil {
-		t.Errorf("Failed to save partial nil pointer struct", err)
+		t.Error("Failed to save partial nil pointer struct", err)
 	}
 
 	var pointerStruct3 PointerStruct
 	if err := DB.First(&pointerStruct3, "id = ?", partialNilPointerStruct1.ID).Error; err != nil || *pointerStruct3.Num != num {
-		t.Errorf("Failed to query saved partial nil pointer struct", err)
+		t.Error("Failed to query saved partial nil pointer struct", err)
 	}
 
 	var normalStruct3 NormalStruct
 	if err := DB.Table(tableName).First(&normalStruct3, "id = ?", partialNilPointerStruct1.ID).Error; err != nil || normalStruct3.Num != num {
-		t.Errorf("Failed to query saved partial pointer struct", err)
+		t.Error("Failed to query saved partial pointer struct", err)
 	}
 
 	var partialNilPointerStruct2 = PointerStruct{Name: &name}
 	if err := DB.Create(&partialNilPointerStruct2).Error; err != nil {
-		t.Errorf("Failed to save partial nil pointer struct", err)
+		t.Error("Failed to save partial nil pointer struct", err)
 	}
 
 	var pointerStruct4 PointerStruct
 	if err := DB.First(&pointerStruct4, "id = ?", partialNilPointerStruct2.ID).Error; err != nil || *pointerStruct4.Name != name {
-		t.Errorf("Failed to query saved partial nil pointer struct", err)
+		t.Error("Failed to query saved partial nil pointer struct", err)
 	}
 
 	var normalStruct4 NormalStruct
 	if err := DB.Table(tableName).First(&normalStruct4, "id = ?", partialNilPointerStruct2.ID).Error; err != nil || normalStruct4.Name != name {
-		t.Errorf("Failed to query saved partial pointer struct", err)
+		t.Error("Failed to query saved partial pointer struct", err)
 	}
 }

postgres.go

@@ -1,154 +0,0 @@
-package gorm
-
-import (
-	"database/sql"
-	"database/sql/driver"
-	"fmt"
-	"reflect"
-	"strings"
-	"time"
-
-	"github.com/lib/pq/hstore"
-)
-
-type postgres struct {
-	commonDialect
-}
-
-func (postgres) BinVar(i int) string {
-	return fmt.Sprintf("$%v", i)
-}
-
-func (postgres) SupportLastInsertId() bool {
-	return false
-}
-
-func (postgres) SqlTag(value reflect.Value, size int, autoIncrease bool) string {
-	switch value.Kind() {
-	case reflect.Bool:
-		return "boolean"
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
-		if autoIncrease {
-			return "serial"
-		}
-		return "integer"
-	case reflect.Int64, reflect.Uint64:
-		if autoIncrease {
-			return "bigserial"
-		}
-		return "bigint"
-	case reflect.Float32, reflect.Float64:
-		return "numeric"
-	case reflect.String:
-		if size > 0 && size < 65532 {
-			return fmt.Sprintf("varchar(%d)", size)
-		}
-		return "text"
-	case reflect.Struct:
-		if _, ok := value.Interface().(time.Time); ok {
-			return "timestamp with time zone"
-		}
-	case reflect.Map:
-		if value.Type() == hstoreType {
-			return "hstore"
-		}
-	default:
-		if isByteArrayOrSlice(value) {
-			return "bytea"
-		} else if isUUID(value) {
-			return "uuid"
-		}
-	}
-	panic(fmt.Sprintf("invalid sql type %s (%s) for postgres", value.Type().Name(), value.Kind().String()))
-}
-
-var byteType = reflect.TypeOf(uint8(0))
-
-func isByteArrayOrSlice(value reflect.Value) bool {
-	return (value.Kind() == reflect.Array || value.Kind() == reflect.Slice) && value.Type().Elem() == byteType
-}
-
-func isUUID(value reflect.Value) bool {
-	if value.Kind() != reflect.Array || value.Type().Len() != 16 {
-		return false
-	}
-	typename := value.Type().Name()
-	lower := strings.ToLower(typename)
-	return "uuid" == lower || "guid" == lower
-}
-
-func (s postgres) ReturningStr(tableName, key string) string {
-	return fmt.Sprintf("RETURNING %v.%v", tableName, key)
-}
-
-func (s postgres) HasTable(scope *Scope, tableName string) bool {
-	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.tables WHERE table_name = ? AND table_type = 'BASE TABLE'", tableName)
-	return count > 0
-}
-
-func (s postgres) HasColumn(scope *Scope, tableName string, columnName string) bool {
-	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.columns WHERE table_name = ? AND column_name = ?", tableName, columnName)
-	return count > 0
-}
-
-func (postgres) RemoveIndex(scope *Scope, indexName string) {
-	scope.Err(scope.NewDB().Exec(fmt.Sprintf("DROP INDEX %v", indexName)).Error)
-}
-
-func (s postgres) HasIndex(scope *Scope, tableName string, indexName string) bool {
-	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM pg_indexes WHERE tablename = ? AND indexname = ?", tableName, indexName)
-	return count > 0
-}
-
-func (s postgres) CurrentDatabase(scope *Scope) (name string) {
-	s.RawScanString(scope, &name, "SELECT CURRENT_DATABASE()")
-	return
-}
-
-var hstoreType = reflect.TypeOf(Hstore{})
-
-type Hstore map[string]*string
-
-func (h Hstore) Value() (driver.Value, error) {
-	hstore := hstore.Hstore{Map: map[string]sql.NullString{}}
-	if len(h) == 0 {
-		return nil, nil
-	}
-
-	for key, value := range h {
-		var s sql.NullString
-		if value != nil {
-			s.String = *value
-			s.Valid = true
-		}
-		hstore.Map[key] = s
-	}
-	return hstore.Value()
-}
-
-func (h *Hstore) Scan(value interface{}) error {
-	hstore := hstore.Hstore{}
-
-	if err := hstore.Scan(value); err != nil {
-		return err
-	}
-
-	if len(hstore.Map) == 0 {
-		return nil
-	}
-
-	*h = Hstore{}
-	for k := range hstore.Map {
-		if hstore.Map[k].Valid {
-			s := hstore.Map[k].String
-			(*h)[k] = &s
-		} else {
-			(*h)[k] = nil
-		}
-	}
-
-	return nil
-}

preload.go

@@ -1,388 +0,0 @@
-package gorm
-
-import (
-	"database/sql/driver"
-	"errors"
-	"fmt"
-	"reflect"
-	"strings"
-)
-
-func getRealValue(value reflect.Value, columns []string) (results []interface{}) {
-	// If value is a nil pointer, Indirect returns a zero Value!
-	// Therefor we need to check for a zero value,
-	// as FieldByName could panic
-	if pointedValue := reflect.Indirect(value); pointedValue.IsValid() {
-		for _, column := range columns {
-			if pointedValue.FieldByName(column).IsValid() {
-				result := pointedValue.FieldByName(column).Interface()
-				if r, ok := result.(driver.Valuer); ok {
-					result, _ = r.Value()
-				}
-				results = append(results, result)
-			}
-		}
-	}
-	return
-}
-
-func equalAsString(a interface{}, b interface{}) bool {
-	return toString(a) == toString(b)
-}
-
-func Preload(scope *Scope) {
-	if scope.Search.preload == nil || scope.HasError() {
-		return
-	}
-
-	preloadMap := map[string]bool{}
-	fields := scope.Fields()
-	for _, preload := range scope.Search.preload {
-		schema, conditions := preload.schema, preload.conditions
-		keys := strings.Split(schema, ".")
-		currentScope := scope
-		currentFields := fields
-		originalConditions := conditions
-		conditions = []interface{}{}
-		for i, key := range keys {
-			var found bool
-			if preloadMap[strings.Join(keys[:i+1], ".")] {
-				goto nextLoop
-			}
-
-			if i == len(keys)-1 {
-				conditions = originalConditions
-			}
-
-			for _, field := range currentFields {
-				if field.Name != key || field.Relationship == nil {
-					continue
-				}
-
-				found = true
-				switch field.Relationship.Kind {
-				case "has_one":
-					currentScope.handleHasOnePreload(field, conditions)
-				case "has_many":
-					currentScope.handleHasManyPreload(field, conditions)
-				case "belongs_to":
-					currentScope.handleBelongsToPreload(field, conditions)
-				case "many_to_many":
-					currentScope.handleManyToManyPreload(field, conditions)
-				default:
-					currentScope.Err(errors.New("not supported relation"))
-				}
-				break
-			}
-
-			if !found {
-				value := reflect.ValueOf(currentScope.Value)
-				if value.Kind() == reflect.Slice && value.Type().Elem().Kind() == reflect.Interface {
-					value = value.Index(0).Elem()
-				}
-				scope.Err(fmt.Errorf("can't find field %s in %s", key, value.Type()))
-				return
-			}
-
-			preloadMap[strings.Join(keys[:i+1], ".")] = true
-
-		nextLoop:
-			if i < len(keys)-1 {
-				currentScope = currentScope.getColumnsAsScope(key)
-				currentFields = currentScope.Fields()
-			}
-		}
-	}
-
-}
-
-func makeSlice(typ reflect.Type) interface{} {
-	if typ.Kind() == reflect.Slice {
-		typ = typ.Elem()
-	}
-	sliceType := reflect.SliceOf(typ)
-	slice := reflect.New(sliceType)
-	slice.Elem().Set(reflect.MakeSlice(sliceType, 0, 0))
-	return slice.Interface()
-}
-
-func (scope *Scope) handleHasOnePreload(field *Field, conditions []interface{}) {
-	relation := field.Relationship
-
-	primaryKeys := scope.getColumnAsArray(relation.AssociationForeignFieldNames)
-	if len(primaryKeys) == 0 {
-		return
-	}
-
-	results := makeSlice(field.Struct.Type)
-	scope.Err(scope.NewDB().Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relation.ForeignDBNames), toQueryMarks(primaryKeys)), toQueryValues(primaryKeys)...).Find(results, conditions...).Error)
-	resultValues := reflect.Indirect(reflect.ValueOf(results))
-
-	for i := 0; i < resultValues.Len(); i++ {
-		result := resultValues.Index(i)
-		if scope.IndirectValue().Kind() == reflect.Slice {
-			value := getRealValue(result, relation.ForeignFieldNames)
-			objects := scope.IndirectValue()
-			for j := 0; j < objects.Len(); j++ {
-				if equalAsString(getRealValue(objects.Index(j), relation.AssociationForeignFieldNames), value) {
-					reflect.Indirect(objects.Index(j)).FieldByName(field.Name).Set(result)
-					break
-				}
-			}
-		} else {
-			if err := scope.SetColumn(field, result); err != nil {
-				scope.Err(err)
-				return
-			}
-		}
-	}
-}
-
-func (scope *Scope) handleHasManyPreload(field *Field, conditions []interface{}) {
-	relation := field.Relationship
-	primaryKeys := scope.getColumnAsArray(relation.AssociationForeignFieldNames)
-	if len(primaryKeys) == 0 {
-		return
-	}
-
-	results := makeSlice(field.Struct.Type)
-	scope.Err(scope.NewDB().Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relation.ForeignDBNames), toQueryMarks(primaryKeys)), toQueryValues(primaryKeys)...).Find(results, conditions...).Error)
-	resultValues := reflect.Indirect(reflect.ValueOf(results))
-
-	if scope.IndirectValue().Kind() == reflect.Slice {
-		preloadMap := make(map[string][]reflect.Value)
-		for i := 0; i < resultValues.Len(); i++ {
-			result := resultValues.Index(i)
-			value := getRealValue(result, relation.ForeignFieldNames)
-			preloadMap[toString(value)] = append(preloadMap[toString(value)], result)
-		}
-
-		objects := scope.IndirectValue()
-		for j := 0; j < objects.Len(); j++ {
-			object := reflect.Indirect(objects.Index(j))
-			objectRealValue := getRealValue(object, relation.AssociationForeignFieldNames)
-			objectStringValue := toString(objectRealValue)
-			if results, ok := preloadMap[objectStringValue]; ok {
-				if object.Kind() == reflect.Ptr {
-					object = object.Elem()
-				}
-				f := object.FieldByName(field.Name)
-				f.Set(reflect.Append(f, results...))
-			}
-		}
-	} else {
-		scope.SetColumn(field, resultValues)
-	}
-}
-
-func (scope *Scope) handleBelongsToPreload(field *Field, conditions []interface{}) {
-	relation := field.Relationship
-	primaryKeys := scope.getColumnAsArray(relation.ForeignFieldNames)
-	if len(primaryKeys) == 0 {
-		return
-	}
-
-	results := makeSlice(field.Struct.Type)
-	scope.Err(scope.NewDB().Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relation.AssociationForeignDBNames), toQueryMarks(primaryKeys)), toQueryValues(primaryKeys)...).Find(results, conditions...).Error)
-	resultValues := reflect.Indirect(reflect.ValueOf(results))
-
-	for i := 0; i < resultValues.Len(); i++ {
-		result := resultValues.Index(i)
-		if scope.IndirectValue().Kind() == reflect.Slice {
-			value := getRealValue(result, relation.AssociationForeignFieldNames)
-			objects := scope.IndirectValue()
-			for j := 0; j < objects.Len(); j++ {
-				object := reflect.Indirect(objects.Index(j))
-				if object.Kind() == reflect.Ptr {
-					object = reflect.Indirect(objects.Index(j).Elem())
-				}
-				if equalAsString(getRealValue(object, relation.ForeignFieldNames), value) {
-					object.FieldByName(field.Name).Set(result)
-				}
-			}
-		} else {
-			scope.SetColumn(field, result)
-		}
-	}
-}
-
-func (scope *Scope) handleManyToManyPreload(field *Field, conditions []interface{}) {
-	relation := field.Relationship
-	joinTableHandler := relation.JoinTableHandler
-	destType := field.StructField.Struct.Type.Elem()
-	var isPtr bool
-	if destType.Kind() == reflect.Ptr {
-		isPtr = true
-		destType = destType.Elem()
-	}
-
-	var sourceKeys []string
-	var linkHash = make(map[string][]reflect.Value)
-
-	for _, key := range joinTableHandler.SourceForeignKeys() {
-		sourceKeys = append(sourceKeys, key.DBName)
-	}
-
-	db := scope.NewDB().Table(scope.New(reflect.New(destType).Interface()).TableName()).Select("*")
-
-	preloadJoinDB := joinTableHandler.JoinWith(joinTableHandler, db, scope.Value)
-
-	if len(conditions) > 0 {
-		preloadJoinDB = preloadJoinDB.Where(conditions[0], conditions[1:]...)
-	}
-	rows, err := preloadJoinDB.Rows()
-
-	if scope.Err(err) != nil {
-		return
-	}
-	defer rows.Close()
-
-	columns, _ := rows.Columns()
-	for rows.Next() {
-		elem := reflect.New(destType).Elem()
-		var values = make([]interface{}, len(columns))
-
-		fields := scope.New(elem.Addr().Interface()).Fields()
-
-		var foundFields = map[string]bool{}
-		for index, column := range columns {
-			if field, ok := fields[column]; ok && !foundFields[column] {
-				if field.Field.Kind() == reflect.Ptr {
-					values[index] = field.Field.Addr().Interface()
-				} else {
-					values[index] = reflect.New(reflect.PtrTo(field.Field.Type())).Interface()
-				}
-				foundFields[column] = true
-			} else {
-				var i interface{}
-				values[index] = &i
-			}
-		}
-
-		scope.Err(rows.Scan(values...))
-
-		var sourceKey []interface{}
-
-		var scannedFields = map[string]bool{}
-		for index, column := range columns {
-			value := values[index]
-			if field, ok := fields[column]; ok && !scannedFields[column] {
-				if field.Field.Kind() == reflect.Ptr {
-					field.Field.Set(reflect.ValueOf(value).Elem())
-				} else if v := reflect.ValueOf(value).Elem().Elem(); v.IsValid() {
-					field.Field.Set(v)
-				}
-				scannedFields[column] = true
-			} else if strInSlice(column, sourceKeys) {
-				sourceKey = append(sourceKey, *(value.(*interface{})))
-			}
-		}
-
-		if len(sourceKey) != 0 {
-			if isPtr {
-				linkHash[toString(sourceKey)] = append(linkHash[toString(sourceKey)], elem.Addr())
-			} else {
-				linkHash[toString(sourceKey)] = append(linkHash[toString(sourceKey)], elem)
-			}
-		}
-	}
-
-	var foreignFieldNames []string
-	for _, dbName := range relation.ForeignFieldNames {
-		if field, ok := scope.FieldByName(dbName); ok {
-			foreignFieldNames = append(foreignFieldNames, field.Name)
-		}
-	}
-
-	if scope.IndirectValue().Kind() == reflect.Slice {
-		objects := scope.IndirectValue()
-		for j := 0; j < objects.Len(); j++ {
-			object := reflect.Indirect(objects.Index(j))
-			if object.Kind() == reflect.Ptr {
-				object = object.Elem()
-			}
-			source := getRealValue(object, foreignFieldNames)
-			field := object.FieldByName(field.Name)
-			for _, link := range linkHash[toString(source)] {
-				field.Set(reflect.Append(field, link))
-			}
-		}
-	} else {
-		if object := scope.IndirectValue(); object.IsValid() {
-			source := getRealValue(object, foreignFieldNames)
-			field := object.FieldByName(field.Name)
-			for _, link := range linkHash[toString(source)] {
-				field.Set(reflect.Append(field, link))
-			}
-		}
-	}
-}
-
-func (scope *Scope) getColumnAsArray(columns []string) (results [][]interface{}) {
-	values := scope.IndirectValue()
-	switch values.Kind() {
-	case reflect.Slice:
-		for i := 0; i < values.Len(); i++ {
-			var result []interface{}
-			for _, column := range columns {
-				value := reflect.Indirect(values.Index(i))
-				if value.Kind() == reflect.Ptr {
-					value = reflect.Indirect(values.Index(i).Elem())
-				}
-				result = append(result, value.FieldByName(column).Interface())
-			}
-			results = append(results, result)
-		}
-	case reflect.Struct:
-		var result []interface{}
-		for _, column := range columns {
-			result = append(result, values.FieldByName(column).Interface())
-		}
-		return [][]interface{}{result}
-	}
-	return
-}
-
-func (scope *Scope) getColumnsAsScope(column string) *Scope {
-	values := scope.IndirectValue()
-	switch values.Kind() {
-	case reflect.Slice:
-		modelType := values.Type().Elem()
-		if modelType.Kind() == reflect.Ptr {
-			modelType = modelType.Elem()
-		}
-		fieldStruct, _ := modelType.FieldByName(column)
-		var columns reflect.Value
-		if fieldStruct.Type.Kind() == reflect.Slice || fieldStruct.Type.Kind() == reflect.Ptr {
-			columns = reflect.New(reflect.SliceOf(reflect.PtrTo(fieldStruct.Type.Elem()))).Elem()
-		} else {
-			columns = reflect.New(reflect.SliceOf(reflect.PtrTo(fieldStruct.Type))).Elem()
-		}
-		for i := 0; i < values.Len(); i++ {
-			column := reflect.Indirect(values.Index(i)).FieldByName(column)
-			if column.Kind() == reflect.Ptr {
-				column = column.Elem()
-			}
-			if column.Kind() == reflect.Slice {
-				for i := 0; i < column.Len(); i++ {
-					elem := column.Index(i)
-					if elem.CanAddr() {
-						columns = reflect.Append(columns, elem.Addr())
-					}
-				}
-			} else {
-				if column.CanAddr() {
-					columns = reflect.Append(columns, column.Addr())
-				}
-			}
-		}
-		return scope.New(columns.Interface())
-	case reflect.Struct:
-		field := values.FieldByName(column)
-		if !field.CanAddr() {
-			return nil
-		}
-		return scope.New(field.Addr().Interface())
-	}
-	return nil
-}

preload_test.go

@@ -133,7 +133,7 @@ func TestNestedPreload1(t *testing.T) {
 		t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
 	}
 
-	if err := DB.Preload("Level2").Preload("Level2.Level1").Find(&got, "name = ?", "not_found").Error; err != gorm.RecordNotFound {
+	if err := DB.Preload("Level2").Preload("Level2.Level1").Find(&got, "name = ?", "not_found").Error; err != gorm.ErrRecordNotFound {
 		t.Error(err)
 	}
 }
@@ -818,90 +818,6 @@ func TestManyToManyPreloadWithMultiPrimaryKeys(t *testing.T) {
 	}
 }
 
-func TestManyToManyPreloadForPointer(t *testing.T) {
-	type (
-		Level1 struct {
-			ID    uint
-			Value string
-		}
-		Level2 struct {
-			ID      uint
-			Value   string
-			Level1s []*Level1 `gorm:"many2many:levels;"`
-		}
-	)
-
-	DB.DropTableIfExists(&Level2{})
-	DB.DropTableIfExists(&Level1{})
-	DB.DropTableIfExists("levels")
-
-	if err := DB.AutoMigrate(&Level2{}, &Level1{}).Error; err != nil {
-		t.Error(err)
-	}
-
-	want := Level2{Value: "Bob", Level1s: []*Level1{
-		{Value: "ru"},
-		{Value: "en"},
-	}}
-	if err := DB.Save(&want).Error; err != nil {
-		t.Error(err)
-	}
-
-	want2 := Level2{Value: "Tom", Level1s: []*Level1{
-		{Value: "zh"},
-		{Value: "de"},
-	}}
-	if err := DB.Save(&want2).Error; err != nil {
-		t.Error(err)
-	}
-
-	var got Level2
-	if err := DB.Preload("Level1s").Find(&got, "value = ?", "Bob").Error; err != nil {
-		t.Error(err)
-	}
-
-	if !reflect.DeepEqual(got, want) {
-		t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
-	}
-
-	var got2 Level2
-	if err := DB.Preload("Level1s").Find(&got2, "value = ?", "Tom").Error; err != nil {
-		t.Error(err)
-	}
-
-	if !reflect.DeepEqual(got2, want2) {
-		t.Errorf("got %s; want %s", toJSONString(got2), toJSONString(want2))
-	}
-
-	var got3 []Level2
-	if err := DB.Preload("Level1s").Find(&got3, "value IN (?)", []string{"Bob", "Tom"}).Error; err != nil {
-		t.Error(err)
-	}
-
-	if !reflect.DeepEqual(got3, []Level2{got, got2}) {
-		t.Errorf("got %s; want %s", toJSONString(got3), toJSONString([]Level2{got, got2}))
-	}
-
-	var got4 []Level2
-	if err := DB.Preload("Level1s", "value IN (?)", []string{"zh", "ru"}).Find(&got4, "value IN (?)", []string{"Bob", "Tom"}).Error; err != nil {
-		t.Error(err)
-	}
-
-	var got5 Level2
-	DB.Preload("Level1s").First(&got5, "value = ?", "bogus")
-
-	var ruLevel1 Level1
-	var zhLevel1 Level1
-	DB.First(&ruLevel1, "value = ?", "ru")
-	DB.First(&zhLevel1, "value = ?", "zh")
-
-	got.Level1s = []*Level1{&ruLevel1}
-	got2.Level1s = []*Level1{&zhLevel1}
-	if !reflect.DeepEqual(got4, []Level2{got, got2}) {
-		t.Errorf("got %s; want %s", toJSONString(got4), toJSONString([]Level2{got, got2}))
-	}
-}
-
 func TestManyToManyPreloadForNestedPointer(t *testing.T) {
 	type (
 		Level1 struct {
@@ -1065,7 +981,7 @@ func TestNestedManyToManyPreload(t *testing.T) {
 		t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
 	}
 
-	if err := DB.Preload("Level2s.Level1s").Find(&got, "value = ?", "not_found").Error; err != gorm.RecordNotFound {
+	if err := DB.Preload("Level2s.Level1s").Find(&got, "value = ?", "not_found").Error; err != gorm.ErrRecordNotFound {
 		t.Error(err)
 	}
 }
@@ -1122,12 +1038,87 @@ func TestNestedManyToManyPreload2(t *testing.T) {
 		t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
 	}
 
-	if err := DB.Preload("Level2.Level1s").Find(&got, "value = ?", "not_found").Error; err != gorm.RecordNotFound {
+	if err := DB.Preload("Level2.Level1s").Find(&got, "value = ?", "not_found").Error; err != gorm.ErrRecordNotFound {
 		t.Error(err)
 	}
 }
 
 func TestNestedManyToManyPreload3(t *testing.T) {
+	type (
+		Level1 struct {
+			ID    uint
+			Value string
+		}
+		Level2 struct {
+			ID      uint
+			Value   string
+			Level1s []*Level1 `gorm:"many2many:level1_level2;"`
+		}
+		Level3 struct {
+			ID       uint
+			Value    string
+			Level2ID sql.NullInt64
+			Level2   *Level2
+		}
+	)
+
+	DB.DropTableIfExists(&Level1{})
+	DB.DropTableIfExists(&Level2{})
+	DB.DropTableIfExists(&Level3{})
+	DB.DropTableIfExists("level1_level2")
+
+	if err := DB.AutoMigrate(&Level3{}, &Level2{}, &Level1{}).Error; err != nil {
+		t.Error(err)
+	}
+
+	level1Zh := &Level1{Value: "zh"}
+	level1Ru := &Level1{Value: "ru"}
+	level1En := &Level1{Value: "en"}
+
+	level21 := &Level2{
+		Value:   "Level2-1",
+		Level1s: []*Level1{level1Zh, level1Ru},
+	}
+
+	level22 := &Level2{
+		Value:   "Level2-2",
+		Level1s: []*Level1{level1Zh, level1En},
+	}
+
+	wants := []*Level3{
+		{
+			Value:  "Level3-1",
+			Level2: level21,
+		},
+		{
+			Value:  "Level3-2",
+			Level2: level22,
+		},
+		{
+			Value:  "Level3-3",
+			Level2: level21,
+		},
+	}
+
+	for _, want := range wants {
+		if err := DB.Save(&want).Error; err != nil {
+			t.Error(err)
+		}
+	}
+
+	var gots []*Level3
+	if err := DB.Preload("Level2.Level1s", func(db *gorm.DB) *gorm.DB {
+		return db.Order("level1.id ASC")
+	}).Find(&gots).Error; err != nil {
+		t.Error(err)
+	}
+
+	if !reflect.DeepEqual(gots, wants) {
+		t.Errorf("got %s; want %s", toJSONString(gots), toJSONString(wants))
+	}
+}
+
+func TestNestedManyToManyPreload4(t *testing.T) {
 	type (
 		Level4 struct {
 			ID       uint
@@ -1185,6 +1176,90 @@ func TestNestedManyToManyPreload3(t *testing.T) {
 	}
 }
 
+func TestManyToManyPreloadForPointer(t *testing.T) {
+	type (
+		Level1 struct {
+			ID    uint
+			Value string
+		}
+		Level2 struct {
+			ID      uint
+			Value   string
+			Level1s []*Level1 `gorm:"many2many:levels;"`
+		}
+	)
+
+	DB.DropTableIfExists(&Level2{})
+	DB.DropTableIfExists(&Level1{})
+	DB.DropTableIfExists("levels")
+
+	if err := DB.AutoMigrate(&Level2{}, &Level1{}).Error; err != nil {
+		t.Error(err)
+	}
+
+	want := Level2{Value: "Bob", Level1s: []*Level1{
+		{Value: "ru"},
+		{Value: "en"},
+	}}
+	if err := DB.Save(&want).Error; err != nil {
+		t.Error(err)
+	}
+
+	want2 := Level2{Value: "Tom", Level1s: []*Level1{
+		{Value: "zh"},
+		{Value: "de"},
+	}}
+	if err := DB.Save(&want2).Error; err != nil {
+		t.Error(err)
+	}
+
+	var got Level2
+	if err := DB.Preload("Level1s").Find(&got, "value = ?", "Bob").Error; err != nil {
+		t.Error(err)
+	}
+
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
+	}
+
+	var got2 Level2
+	if err := DB.Preload("Level1s").Find(&got2, "value = ?", "Tom").Error; err != nil {
+		t.Error(err)
+	}
+
+	if !reflect.DeepEqual(got2, want2) {
+		t.Errorf("got %s; want %s", toJSONString(got2), toJSONString(want2))
+	}
+
+	var got3 []Level2
+	if err := DB.Preload("Level1s").Find(&got3, "value IN (?)", []string{"Bob", "Tom"}).Error; err != nil {
+		t.Error(err)
+	}
+
+	if !reflect.DeepEqual(got3, []Level2{got, got2}) {
+		t.Errorf("got %s; want %s", toJSONString(got3), toJSONString([]Level2{got, got2}))
+	}
+
+	var got4 []Level2
+	if err := DB.Preload("Level1s", "value IN (?)", []string{"zh", "ru"}).Find(&got4, "value IN (?)", []string{"Bob", "Tom"}).Error; err != nil {
+		t.Error(err)
+	}
+
+	var got5 Level2
+	DB.Preload("Level1s").First(&got5, "value = ?", "bogus")
+
+	var ruLevel1 Level1
+	var zhLevel1 Level1
+	DB.First(&ruLevel1, "value = ?", "ru")
+	DB.First(&zhLevel1, "value = ?", "zh")
+
+	got.Level1s = []*Level1{&ruLevel1}
+	got2.Level1s = []*Level1{&zhLevel1}
+	if !reflect.DeepEqual(got4, []Level2{got, got2}) {
+		t.Errorf("got %s; want %s", toJSONString(got4), toJSONString([]Level2{got, got2}))
+	}
+}
+
 func TestNilPointerSlice(t *testing.T) {
 	type (
 		Level3 struct {
@@ -1234,7 +1309,7 @@ func TestNilPointerSlice(t *testing.T) {
 	}
 
 	if len(got) != 2 {
-		t.Error("got %v items, expected 2", len(got))
+		t.Errorf("got %v items, expected 2", len(got))
 	}
 
 	if !reflect.DeepEqual(got[0], want) && !reflect.DeepEqual(got[1], want) {

query_test.go

@@ -629,14 +629,3 @@ func TestSelectWithArrayInput(t *testing.T) {
 		t.Errorf("Should have selected both age and name")
 	}
 }
-
-func TestCurrentDatabase(t *testing.T) {
-	databaseName := DB.CurrentDatabase()
-	if err := DB.Error; err != nil {
-		t.Errorf("Problem getting current db name: %s", err)
-	}
-	if databaseName == "" {
-		t.Errorf("Current db name returned empty; this should never happen!")
-	}
-	t.Logf("Got current db name: %v", databaseName)
-}

scope.go

@@ -1,48 +1,32 @@
 package gorm
 
 import (
+	"database/sql"
 	"errors"
 	"fmt"
 	"regexp"
 	"strings"
-	"time"
 
 	"reflect"
 )
 
+// Scope contain current operation's information when you perform any operation on the database
 type Scope struct {
 	Search          *search
 	Value           interface{}
-	Sql             string
+	SQL             string
-	SqlVars         []interface{}
+	SQLVars         []interface{}
 	db              *DB
-	indirectValue   *reflect.Value
+	instanceID      string
-	instanceId      string
 	primaryKeyField *Field
 	skipLeft        bool
 	fields          map[string]*Field
 	selectAttrs     *[]string
 }
 
+// IndirectValue return scope's reflect value's indirect value
 func (scope *Scope) IndirectValue() reflect.Value {
-	if scope.indirectValue == nil {
+	return indirect(reflect.ValueOf(scope.Value))
-		value := reflect.Indirect(reflect.ValueOf(scope.Value))
-		if value.Kind() == reflect.Ptr {
-			value = value.Elem()
-		}
-		scope.indirectValue = &value
-	}
-	return *scope.indirectValue
-}
-
-func (scope *Scope) NeedPtr() *Scope {
-	reflectKind := reflect.ValueOf(scope.Value).Kind()
-	if !((reflectKind == reflect.Invalid) || (reflectKind == reflect.Ptr)) {
-		err := fmt.Errorf("%v %v\n", fileWithLineNum(), "using unaddressable value")
-		scope.Err(err)
-		fmt.Printf(err.Error())
-	}
-	return scope
 }
 
 // New create a new Scope without search information
@@ -61,12 +45,13 @@ func (scope *Scope) NewDB() *DB {
 	return nil
 }
 
+// DB return scope's DB connection
 func (scope *Scope) DB() *DB {
 	return scope.db
 }
 
-// SqlDB return *sql.DB
+// SQLDB return *sql.DB
-func (scope *Scope) SqlDB() sqlCommon {
+func (scope *Scope) SQLDB() sqlCommon {
 	return scope.db.db
 }
 
@@ -75,7 +60,7 @@ func (scope *Scope) SkipLeft() {
 	scope.skipLeft = true
 }
 
-// Quote used to quote database column name according to database dialect
+// Quote used to quote string to escape them for database
 func (scope *Scope) Quote(str string) string {
 	if strings.Index(str, ".") != -1 {
 		newStrs := []string{}
@@ -83,12 +68,12 @@ func (scope *Scope) Quote(str string) string {
 			newStrs = append(newStrs, scope.Dialect().Quote(str))
 		}
 		return strings.Join(newStrs, ".")
-	} else {
-		return scope.Dialect().Quote(str)
-	}
 	}
 
-func (scope *Scope) QuoteIfPossible(str string) string {
+	return scope.Dialect().Quote(str)
+}
+
+func (scope *Scope) quoteIfPossible(str string) string {
 	if regexp.MustCompile("^[a-zA-Z]+(.[a-zA-Z]+)*$").MatchString(str) {
 		return scope.Quote(str)
 	}
@@ -100,7 +85,7 @@ func (scope *Scope) Dialect() Dialect {
 	return scope.db.parent.dialect
 }
 
-// Err write error
+// Err add error to Scope
 func (scope *Scope) Err(err error) error {
 	if err != nil {
 		scope.db.AddError(err)
@@ -118,27 +103,30 @@ func (scope *Scope) HasError() bool {
 	return scope.db.Error != nil
 }
 
-func (scope *Scope) PrimaryFields() []*Field {
+// PrimaryFields return scope's primary fields
-	var fields = []*Field{}
+func (scope *Scope) PrimaryFields() (fields []*Field) {
-	for _, field := range scope.GetModelStruct().PrimaryFields {
+	for _, field := range scope.Fields() {
-		fields = append(fields, scope.Fields()[field.DBName])
+		if field.IsPrimaryKey {
+			fields = append(fields, field)
+		}
 	}
 	return fields
 }
 
+// PrimaryField return scope's main primary field, if defined more that one primary fields, will return the one having column name `id` or the first one
 func (scope *Scope) PrimaryField() *Field {
 	if primaryFields := scope.GetModelStruct().PrimaryFields; len(primaryFields) > 0 {
 		if len(primaryFields) > 1 {
-			if field, ok := scope.Fields()["id"]; ok {
+			if field, ok := scope.FieldByName("id"); ok {
 				return field
 			}
 		}
-		return scope.Fields()[primaryFields[0].DBName]
+		return scope.PrimaryFields()[0]
 	}
 	return nil
 }
 
-// PrimaryKey get the primary key's column name
+// PrimaryKey get main primary field's db name
 func (scope *Scope) PrimaryKey() string {
 	if field := scope.PrimaryField(); field != nil {
 		return field.DBName
@@ -146,7 +134,7 @@ func (scope *Scope) PrimaryKey() string {
 	return ""
 }
 
-// PrimaryKeyZero check the primary key is blank or not
+// PrimaryKeyZero check main primary field's value is blank or not
 func (scope *Scope) PrimaryKeyZero() bool {
 	field := scope.PrimaryField()
 	return field == nil || field.IsBlank
@@ -170,80 +158,85 @@ func (scope *Scope) HasColumn(column string) bool {
 	return false
 }
 
-// SetColumn to set the column's value
+// SetColumn to set the column's value, column could be field or field's name/dbname
 func (scope *Scope) SetColumn(column interface{}, value interface{}) error {
+	var updateAttrs = map[string]interface{}{}
+	if attrs, ok := scope.InstanceGet("gorm:update_attrs"); ok {
+		updateAttrs = attrs.(map[string]interface{})
+		defer scope.InstanceSet("gorm:update_attrs", updateAttrs)
+	}
+
 	if field, ok := column.(*Field); ok {
+		updateAttrs[field.DBName] = value
 		return field.Set(value)
 	} else if name, ok := column.(string); ok {
-
+		var (
-		if field, ok := scope.Fields()[name]; ok {
+			dbName           = ToDBName(name)
+			mostMatchedField *Field
+		)
+		for _, field := range scope.Fields() {
+			if field.DBName == value {
+				updateAttrs[field.DBName] = value
 				return field.Set(value)
 			}
-
+			if (field.DBName == dbName) || (field.Name == name && mostMatchedField == nil) {
-		dbName := ToDBName(name)
+				mostMatchedField = field
-		if field, ok := scope.Fields()[dbName]; ok {
+			}
-			return field.Set(value)
 		}
 
-		if field, ok := scope.FieldByName(name); ok {
+		if mostMatchedField != nil {
-			return field.Set(value)
+			updateAttrs[mostMatchedField.DBName] = value
+			return mostMatchedField.Set(value)
 		}
 	}
 	return errors.New("could not convert column to field")
 }
 
-func (scope *Scope) CallMethod(name string, checkError bool) {
+func (scope *Scope) callMethod(methodName string, reflectValue reflect.Value) {
-	if scope.Value == nil || (checkError && scope.HasError()) {
+	if reflectValue.CanAddr() {
+		reflectValue = reflectValue.Addr()
+	}
+
+	if methodValue := reflectValue.MethodByName(methodName); methodValue.IsValid() {
+		switch method := methodValue.Interface().(type) {
+		case func():
+			method()
+		case func(*Scope):
+			method(scope)
+		case func(*DB):
+			newDB := scope.NewDB()
+			method(newDB)
+			scope.Err(newDB.Error)
+		case func() error:
+			scope.Err(method())
+		case func(*Scope) error:
+			scope.Err(method(scope))
+		case func(*DB) error:
+			newDB := scope.NewDB()
+			scope.Err(method(newDB))
+			scope.Err(newDB.Error)
+		default:
+			scope.Err(fmt.Errorf("unsupported function %v", methodName))
+		}
+	}
+}
+
+// CallMethod call scope value's method, if it is a slice, will call its element's method one by one
+func (scope *Scope) CallMethod(methodName string) {
+	if scope.Value == nil {
 		return
 	}
 
-	call := func(value interface{}) {
+	if indirectScopeValue := scope.IndirectValue(); indirectScopeValue.Kind() == reflect.Slice {
-		if fm := reflect.ValueOf(value).MethodByName(name); fm.IsValid() {
+		for i := 0; i < indirectScopeValue.Len(); i++ {
-			switch f := fm.Interface().(type) {
+			scope.callMethod(methodName, indirectScopeValue.Index(i))
-			case func():
-				f()
-			case func(s *Scope):
-				f(scope)
-			case func(s *DB):
-				newDB := scope.NewDB()
-				f(newDB)
-				scope.Err(newDB.Error)
-			case func() error:
-				scope.Err(f())
-			case func(s *Scope) error:
-				scope.Err(f(scope))
-			case func(s *DB) error:
-				newDB := scope.NewDB()
-				scope.Err(f(newDB))
-				scope.Err(newDB.Error)
-			default:
-				scope.Err(fmt.Errorf("unsupported function %v", name))
-			}
-		}
-	}
-
-	if values := scope.IndirectValue(); values.Kind() == reflect.Slice {
-		for i := 0; i < values.Len(); i++ {
-			value := values.Index(i).Addr().Interface()
-			if values.Index(i).Kind() == reflect.Ptr {
-				value = values.Index(i).Interface()
-			}
-			call(value)
 		}
 	} else {
-		if scope.IndirectValue().CanAddr() {
+		scope.callMethod(methodName, indirectScopeValue)
-			call(scope.IndirectValue().Addr().Interface())
-		} else {
-			call(scope.IndirectValue().Interface())
-		}
 	}
 }
 
-func (scope *Scope) CallMethodWithErrorCheck(name string) {
+// AddToVars add value as sql's vars, used to prevent SQL injection
-	scope.CallMethod(name, true)
-}
-
-// AddToVars add value as sql's vars, gorm will escape them
 func (scope *Scope) AddToVars(value interface{}) string {
 	if expr, ok := value.(*expr); ok {
 		exp := expr.expr
@@ -251,10 +244,10 @@ func (scope *Scope) AddToVars(value interface{}) string {
 			exp = strings.Replace(exp, "?", scope.AddToVars(arg), 1)
 		}
 		return exp
-	} else {
-		scope.SqlVars = append(scope.SqlVars, value)
-		return scope.Dialect().BinVar(len(scope.SqlVars))
 	}
+
+	scope.SQLVars = append(scope.SQLVars, value)
+	return scope.Dialect().BindVar(len(scope.SQLVars))
 }
 
 type tabler interface {
@@ -265,7 +258,7 @@ type dbTabler interface {
 	TableName(*DB) string
 }
 
-// TableName get table name
+// TableName return table name
 func (scope *Scope) TableName() string {
 	if scope.Search != nil && len(scope.Search.tableName) > 0 {
 		return scope.Search.tableName
@@ -282,44 +275,54 @@ func (scope *Scope) TableName() string {
 	return scope.GetModelStruct().TableName(scope.db.Model(scope.Value))
 }
 
+// QuotedTableName return quoted table name
 func (scope *Scope) QuotedTableName() (name string) {
 	if scope.Search != nil && len(scope.Search.tableName) > 0 {
 		if strings.Index(scope.Search.tableName, " ") != -1 {
 			return scope.Search.tableName
 		}
 		return scope.Quote(scope.Search.tableName)
-	} else {
+	}
+
 	return scope.Quote(scope.TableName())
 }
-}
 
-// CombinedConditionSql get combined condition sql
+// CombinedConditionSql return combined condition sql
 func (scope *Scope) CombinedConditionSql() string {
-	return scope.joinsSql() + scope.whereSql() + scope.groupSql() +
+	return scope.joinsSQL() + scope.whereSQL() + scope.groupSQL() +
-		scope.havingSql() + scope.orderSql() + scope.limitSql() + scope.offsetSql()
+		scope.havingSQL() + scope.orderSQL() + scope.limitAndOffsetSQL()
 }
 
+// FieldByName find `gorm.Field` with field name or db name
 func (scope *Scope) FieldByName(name string) (field *Field, ok bool) {
+	var (
+		dbName           = ToDBName(name)
+		mostMatchedField *Field
+	)
+
 	for _, field := range scope.Fields() {
 		if field.Name == name || field.DBName == name {
 			return field, true
 		}
+		if field.DBName == dbName {
+			mostMatchedField = field
 		}
-	return nil, false
+	}
+	return mostMatchedField, mostMatchedField != nil
 }
 
-// Raw set sql
+// Raw set raw sql
 func (scope *Scope) Raw(sql string) *Scope {
-	scope.Sql = strings.Replace(sql, "$$", "?", -1)
+	scope.SQL = strings.Replace(sql, "$$", "?", -1)
 	return scope
 }
 
-// Exec invoke sql
+// Exec perform generated SQL
 func (scope *Scope) Exec() *Scope {
-	defer scope.Trace(NowFunc())
+	defer scope.trace(NowFunc())
 
 	if !scope.HasError() {
-		if result, err := scope.SqlDB().Exec(scope.Sql, scope.SqlVars...); scope.Err(err) == nil {
+		if result, err := scope.SQLDB().Exec(scope.SQL, scope.SQLVars...); scope.Err(err) == nil {
 			if count, err := result.RowsAffected(); scope.Err(err) == nil {
 				scope.db.RowsAffected = count
 			}
@@ -334,37 +337,32 @@ func (scope *Scope) Set(name string, value interface{}) *Scope {
 	return scope
 }
 
-// Get get value by name
+// Get get setting by name
 func (scope *Scope) Get(name string) (interface{}, bool) {
 	return scope.db.Get(name)
 }
 
-// InstanceId get InstanceId for scope
+// InstanceID get InstanceID for scope
-func (scope *Scope) InstanceId() string {
+func (scope *Scope) InstanceID() string {
-	if scope.instanceId == "" {
+	if scope.instanceID == "" {
-		scope.instanceId = fmt.Sprintf("%v%v", &scope, &scope.db)
+		scope.instanceID = fmt.Sprintf("%v%v", &scope, &scope.db)
 	}
-	return scope.instanceId
+	return scope.instanceID
 }
 
+// InstanceSet set instance setting for current operation, but not for operations in callbacks, like saving associations callback
 func (scope *Scope) InstanceSet(name string, value interface{}) *Scope {
-	return scope.Set(name+scope.InstanceId(), value)
+	return scope.Set(name+scope.InstanceID(), value)
 }
 
+// InstanceGet get instance setting from current operation
 func (scope *Scope) InstanceGet(name string) (interface{}, bool) {
-	return scope.Get(name + scope.InstanceId())
+	return scope.Get(name + scope.InstanceID())
-}
-
-// Trace print sql log
-func (scope *Scope) Trace(t time.Time) {
-	if len(scope.Sql) > 0 {
-		scope.db.slog(scope.Sql, t, scope.SqlVars...)
-	}
 }
 
 // Begin start a transaction
 func (scope *Scope) Begin() *Scope {
-	if db, ok := scope.SqlDB().(sqlDb); ok {
+	if db, ok := scope.SQLDB().(sqlDb); ok {
 		if tx, err := db.Begin(); err == nil {
 			scope.db.db = interface{}(tx).(sqlCommon)
 			scope.InstanceSet("gorm:started_transaction", true)
@@ -373,7 +371,7 @@ func (scope *Scope) Begin() *Scope {
 	return scope
 }
 
-// CommitOrRollback commit current transaction if there is no error, otherwise rollback it
+// CommitOrRollback commit current transaction if no error happened, otherwise will rollback it
 func (scope *Scope) CommitOrRollback() *Scope {
 	if _, ok := scope.InstanceGet("gorm:started_transaction"); ok {
 		if db, ok := scope.db.db.(sqlTx); ok {
@@ -388,6 +386,7 @@ func (scope *Scope) CommitOrRollback() *Scope {
 	return scope
 }
 
+// SelectAttrs return selected attributes
 func (scope *Scope) SelectAttrs() []string {
 	if scope.selectAttrs == nil {
 		attrs := []string{}
@@ -407,57 +406,38 @@ func (scope *Scope) SelectAttrs() []string {
 	return *scope.selectAttrs
 }
 
+// OmitAttrs return omited attributes
 func (scope *Scope) OmitAttrs() []string {
 	return scope.Search.omits
 }
 
-func (scope *Scope) changeableDBColumn(column string) bool {
+func (scope *Scope) scan(rows *sql.Rows, columns []string, fieldsMap map[string]*Field) {
-	selectAttrs := scope.SelectAttrs()
+	var values = make([]interface{}, len(columns))
-	omitAttrs := scope.OmitAttrs()
+	var ignored interface{}
 
-	if len(selectAttrs) > 0 {
+	for index, column := range columns {
-		for _, attr := range selectAttrs {
+		if field, ok := fieldsMap[column]; ok {
-			if column == ToDBName(attr) {
+			if field.Field.Kind() == reflect.Ptr {
-				return true
+				values[index] = field.Field.Addr().Interface()
+			} else {
+				reflectValue := reflect.New(reflect.PtrTo(field.Struct.Type))
+				reflectValue.Elem().Set(field.Field.Addr())
+				values[index] = reflectValue.Interface()
 			}
-		}
+		} else {
-		return false
+			values[index] = &ignored
-	}
-
-	for _, attr := range omitAttrs {
-		if column == ToDBName(attr) {
-			return false
-		}
-	}
-	return true
-}
-
-func (scope *Scope) changeableField(field *Field) bool {
-	selectAttrs := scope.SelectAttrs()
-	omitAttrs := scope.OmitAttrs()
-
-	if len(selectAttrs) > 0 {
-		for _, attr := range selectAttrs {
-			if field.Name == attr || field.DBName == attr {
-				return true
-			}
-		}
-		return false
-	}
-
-	for _, attr := range omitAttrs {
-		if field.Name == attr || field.DBName == attr {
-			return false
 		}
 	}
 
-	return !field.IsIgnored
+	scope.Err(rows.Scan(values...))
-}
 
-func (scope *Scope) shouldSaveAssociations() bool {
+	for index, column := range columns {
-	saveAssociations, ok := scope.Get("gorm:save_associations")
+		if field, ok := fieldsMap[column]; ok {
-	if ok && !saveAssociations.(bool) {
+			if field.Field.Kind() != reflect.Ptr {
-		return false
+				if v := reflect.ValueOf(values[index]).Elem().Elem(); v.IsValid() {
+					field.Field.Set(v)
+				}
+			}
+		}
 	}
-	return true && !scope.HasError()
 }

scope_private.go

@@ -8,6 +8,7 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
+	"time"
 )
 
 func (scope *Scope) primaryCondition(value interface{}) string {
@@ -75,7 +76,7 @@ func (scope *Scope) buildWhereCondition(clause map[string]interface{}) (str stri
 }
 
 func (scope *Scope) buildNotCondition(clause map[string]interface{}) (str string) {
-	var notEqualSql string
+	var notEqualSQL string
 	var primaryKey = scope.PrimaryKey()
 
 	switch value := clause["query"].(type) {
@@ -86,10 +87,10 @@ func (scope *Scope) buildNotCondition(clause map[string]interface{}) (str string
 			return fmt.Sprintf("(%v <> %v)", scope.Quote(primaryKey), id)
 		} else if regexp.MustCompile("(?i) (=|<>|>|<|LIKE|IS|IN) ").MatchString(value) {
 			str = fmt.Sprintf(" NOT (%v) ", value)
-			notEqualSql = fmt.Sprintf("NOT (%v)", value)
+			notEqualSQL = fmt.Sprintf("NOT (%v)", value)
 		} else {
 			str = fmt.Sprintf("(%v NOT IN (?))", scope.Quote(value))
-			notEqualSql = fmt.Sprintf("(%v <> ?)", scope.Quote(value))
+			notEqualSQL = fmt.Sprintf("(%v <> ?)", scope.Quote(value))
 		}
 	case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, sql.NullInt64:
 		return fmt.Sprintf("(%v <> %v)", scope.Quote(primaryKey), value)
@@ -138,7 +139,7 @@ func (scope *Scope) buildNotCondition(clause map[string]interface{}) (str string
 			if scanner, ok := interface{}(arg).(driver.Valuer); ok {
 				arg, _ = scanner.Value()
 			}
-			str = strings.Replace(notEqualSql, "?", scope.AddToVars(arg), 1)
+			str = strings.Replace(notEqualSQL, "?", scope.AddToVars(arg), 1)
 		}
 	}
 	return
@@ -172,17 +173,20 @@ func (scope *Scope) buildSelectQuery(clause map[string]interface{}) (str string)
 	return
 }
 
-func (scope *Scope) whereSql() (sql string) {
+func (scope *Scope) whereSQL() (sql string) {
-	var primaryConditions, andConditions, orConditions []string
+	var (
+		quotedTableName                                = scope.QuotedTableName()
+		primaryConditions, andConditions, orConditions []string
+	)
 
-	if !scope.Search.Unscoped && scope.Fields()["deleted_at"] != nil {
+	if !scope.Search.Unscoped && scope.HasColumn("deleted_at") {
-		sql := fmt.Sprintf("(%v.deleted_at IS NULL OR %v.deleted_at <= '0001-01-02')", scope.QuotedTableName(), scope.QuotedTableName())
+		sql := fmt.Sprintf("%v.deleted_at IS NULL", quotedTableName)
 		primaryConditions = append(primaryConditions, sql)
 	}
 
 	if !scope.PrimaryKeyZero() {
 		for _, field := range scope.PrimaryFields() {
-			sql := fmt.Sprintf("(%v = %v)", scope.Quote(field.DBName), scope.AddToVars(field.Field.Interface()))
+			sql := fmt.Sprintf("%v.%v = %v", quotedTableName, scope.Quote(field.DBName), scope.AddToVars(field.Field.Interface()))
 			primaryConditions = append(primaryConditions, sql)
 		}
 	}
@@ -205,30 +209,30 @@ func (scope *Scope) whereSql() (sql string) {
 		}
 	}
 
-	orSql := strings.Join(orConditions, " OR ")
+	orSQL := strings.Join(orConditions, " OR ")
-	combinedSql := strings.Join(andConditions, " AND ")
+	combinedSQL := strings.Join(andConditions, " AND ")
-	if len(combinedSql) > 0 {
+	if len(combinedSQL) > 0 {
-		if len(orSql) > 0 {
+		if len(orSQL) > 0 {
-			combinedSql = combinedSql + " OR " + orSql
+			combinedSQL = combinedSQL + " OR " + orSQL
 		}
 	} else {
-		combinedSql = orSql
+		combinedSQL = orSQL
 	}
 
 	if len(primaryConditions) > 0 {
 		sql = "WHERE " + strings.Join(primaryConditions, " AND ")
-		if len(combinedSql) > 0 {
+		if len(combinedSQL) > 0 {
-			sql = sql + " AND (" + combinedSql + ")"
+			sql = sql + " AND (" + combinedSQL + ")"
 		}
-	} else if len(combinedSql) > 0 {
+	} else if len(combinedSQL) > 0 {
-		sql = "WHERE " + combinedSql
+		sql = "WHERE " + combinedSQL
 	}
 	return
 }
 
-func (scope *Scope) selectSql() string {
+func (scope *Scope) selectSQL() string {
 	if len(scope.Search.selects) == 0 {
-		if scope.Search.joins != "" {
+		if len(scope.Search.joinConditions) > 0 {
 			return fmt.Sprintf("%v.*", scope.QuotedTableName())
 		}
 		return "*"
@@ -236,87 +240,60 @@ func (scope *Scope) selectSql() string {
 	return scope.buildSelectQuery(scope.Search.selects)
 }
 
-func (scope *Scope) orderSql() string {
+func (scope *Scope) orderSQL() string {
 	if len(scope.Search.orders) == 0 || scope.Search.countingQuery {
 		return ""
 	}
 	return " ORDER BY " + strings.Join(scope.Search.orders, ",")
 }
 
-func (scope *Scope) limitSql() string {
+func (scope *Scope) limitAndOffsetSQL() string {
-	if !scope.Dialect().HasTop() {
+	return scope.Dialect().LimitAndOffsetSQL(scope.Search.limit, scope.Search.offset)
-		if len(scope.Search.limit) == 0 {
-			return ""
-		}
-		return " LIMIT " + scope.Search.limit
 }
 
-	return ""
+func (scope *Scope) groupSQL() string {
-}
-
-func (scope *Scope) topSql() string {
-	if scope.Dialect().HasTop() && len(scope.Search.offset) == 0 {
-		if len(scope.Search.limit) == 0 {
-			return ""
-		}
-		return " TOP(" + scope.Search.limit + ")"
-	}
-
-	return ""
-}
-
-func (scope *Scope) offsetSql() string {
-	if len(scope.Search.offset) == 0 {
-		return ""
-	}
-
-	if scope.Dialect().HasTop() {
-		sql := " OFFSET " + scope.Search.offset + " ROW "
-		if len(scope.Search.limit) > 0 {
-			sql += "FETCH NEXT " + scope.Search.limit + " ROWS ONLY"
-		}
-		return sql
-	}
-	return " OFFSET " + scope.Search.offset
-}
-
-func (scope *Scope) groupSql() string {
 	if len(scope.Search.group) == 0 {
 		return ""
 	}
 	return " GROUP BY " + scope.Search.group
 }
 
-func (scope *Scope) havingSql() string {
+func (scope *Scope) havingSQL() string {
-	if scope.Search.havingConditions == nil {
+	if len(scope.Search.havingConditions) == 0 {
 		return ""
 	}
 
 	var andConditions []string
-
 	for _, clause := range scope.Search.havingConditions {
 		if sql := scope.buildWhereCondition(clause); sql != "" {
 			andConditions = append(andConditions, sql)
 		}
 	}
 
-	combinedSql := strings.Join(andConditions, " AND ")
+	combinedSQL := strings.Join(andConditions, " AND ")
-	if len(combinedSql) == 0 {
+	if len(combinedSQL) == 0 {
 		return ""
 	}
 
-	return " HAVING " + combinedSql
+	return " HAVING " + combinedSQL
 }
 
-func (scope *Scope) joinsSql() string {
+func (scope *Scope) joinsSQL() string {
-	return scope.Search.joins + " "
+	var joinConditions []string
+	for _, clause := range scope.Search.joinConditions {
+		if sql := scope.buildWhereCondition(clause); sql != "" {
+			joinConditions = append(joinConditions, strings.TrimSuffix(strings.TrimPrefix(sql, "("), ")"))
+		}
 	}
 
-func (scope *Scope) prepareQuerySql() {
+	return strings.Join(joinConditions, " ") + " "
+}
+
+func (scope *Scope) prepareQuerySQL() {
 	if scope.Search.raw {
 		scope.Raw(strings.TrimSuffix(strings.TrimPrefix(scope.CombinedConditionSql(), " WHERE ("), ")"))
 	} else {
-		scope.Raw(fmt.Sprintf("SELECT %v %v FROM %v %v", scope.topSql(), scope.selectSql(), scope.QuotedTableName(), scope.CombinedConditionSql()))
+		scope.Raw(fmt.Sprintf("SELECT %v FROM %v %v", scope.selectSQL(), scope.QuotedTableName(), scope.CombinedConditionSql()))
 	}
 	return
 }
@@ -338,61 +315,53 @@ func (scope *Scope) callCallbacks(funcs []*func(s *Scope)) *Scope {
 	return scope
 }
 
-func (scope *Scope) updatedAttrsWithValues(values map[string]interface{}, ignoreProtectedAttrs bool) (results map[string]interface{}, hasUpdate bool) {
+func (scope *Scope) updatedAttrsWithValues(values map[string]interface{}) (results map[string]interface{}, hasUpdate bool) {
-	if !scope.IndirectValue().CanAddr() {
+	if scope.IndirectValue().Kind() != reflect.Struct {
 		return values, true
 	}
 
-	var hasExpr bool
+	results = map[string]interface{}{}
 	for key, value := range values {
-		if field, ok := scope.FieldByName(key); ok && field.Field.IsValid() {
+		if field, ok := scope.FieldByName(key); ok && scope.changeableField(field) {
 			if !reflect.DeepEqual(field.Field, reflect.ValueOf(value)) {
 				if _, ok := value.(*expr); ok {
-					hasExpr = true
-				} else if !equalAsString(field.Field.Interface(), value) {
 					hasUpdate = true
+					results[field.DBName] = value
+				} else if !equalAsString(field.Field.Interface(), value) {
+					field.Set(value)
+					if field.IsNormal {
+						hasUpdate = true
+						results[field.DBName] = field.Field.Interface()
+					}
+				}
+			} else {
 				field.Set(value)
 			}
 		}
 	}
-	}
-
-	if hasExpr {
-		var updateMap = map[string]interface{}{}
-		for key, field := range scope.Fields() {
-			if field.IsNormal {
-				if v, ok := values[key]; ok {
-					updateMap[key] = v
-				} else {
-					updateMap[key] = field.Field.Interface()
-				}
-			}
-		}
-		return updateMap, true
-	}
 	return
 }
 
 func (scope *Scope) row() *sql.Row {
-	defer scope.Trace(NowFunc())
+	defer scope.trace(NowFunc())
-	scope.callCallbacks(scope.db.parent.callback.rowQueries)
+	scope.callCallbacks(scope.db.parent.callbacks.rowQueries)
-	scope.prepareQuerySql()
+	scope.prepareQuerySQL()
-	return scope.SqlDB().QueryRow(scope.Sql, scope.SqlVars...)
+	return scope.SQLDB().QueryRow(scope.SQL, scope.SQLVars...)
 }
 
 func (scope *Scope) rows() (*sql.Rows, error) {
-	defer scope.Trace(NowFunc())
+	defer scope.trace(NowFunc())
-	scope.callCallbacks(scope.db.parent.callback.rowQueries)
+	scope.callCallbacks(scope.db.parent.callbacks.rowQueries)
-	scope.prepareQuerySql()
+	scope.prepareQuerySQL()
-	return scope.SqlDB().Query(scope.Sql, scope.SqlVars...)
+	return scope.SQLDB().Query(scope.SQL, scope.SQLVars...)
 }
 
 func (scope *Scope) initialize() *Scope {
 	for _, clause := range scope.Search.whereConditions {
-		scope.updatedAttrsWithValues(convertInterfaceToMap(clause["query"]), false)
+		scope.updatedAttrsWithValues(convertInterfaceToMap(clause["query"]))
 	}
-	scope.updatedAttrsWithValues(convertInterfaceToMap(scope.Search.initAttrs), false)
+	scope.updatedAttrsWithValues(convertInterfaceToMap(scope.Search.initAttrs))
-	scope.updatedAttrsWithValues(convertInterfaceToMap(scope.Search.assignAttrs), false)
+	scope.updatedAttrsWithValues(convertInterfaceToMap(scope.Search.assignAttrs))
 	return scope
 }
 
@@ -433,23 +402,45 @@ func (scope *Scope) typeName() string {
 	return typ.Name()
 }
 
+// trace print sql log
+func (scope *Scope) trace(t time.Time) {
+	if len(scope.SQL) > 0 {
+		scope.db.slog(scope.SQL, t, scope.SQLVars...)
+	}
+}
+
+func (scope *Scope) changeableField(field *Field) bool {
+	if selectAttrs := scope.SelectAttrs(); len(selectAttrs) > 0 {
+		for _, attr := range selectAttrs {
+			if field.Name == attr || field.DBName == attr {
+				return true
+			}
+		}
+		return false
+	}
+
+	for _, attr := range scope.OmitAttrs() {
+		if field.Name == attr || field.DBName == attr {
+			return false
+		}
+	}
+
+	return true
+}
+
+func (scope *Scope) shouldSaveAssociations() bool {
+	if saveAssociations, ok := scope.Get("gorm:save_associations"); ok && !saveAssociations.(bool) {
+		return false
+	}
+	return true && !scope.HasError()
+}
+
 func (scope *Scope) related(value interface{}, foreignKeys ...string) *Scope {
 	toScope := scope.db.NewScope(value)
-	fromFields := scope.Fields()
-	toFields := toScope.Fields()
 
 	for _, foreignKey := range append(foreignKeys, toScope.typeName()+"Id", scope.typeName()+"Id") {
-		var fromField, toField *Field
+		fromField, _ := scope.FieldByName(foreignKey)
-		if field, ok := scope.FieldByName(foreignKey); ok {
+		toField, _ := toScope.FieldByName(foreignKey)
-			fromField = field
-		} else {
-			fromField = fromFields[ToDBName(foreignKey)]
-		}
-		if field, ok := toScope.FieldByName(foreignKey); ok {
-			toField = field
-		} else {
-			toField = toFields[ToDBName(foreignKey)]
-		}
 
 		if fromField != nil {
 			if relationship := fromField.Relationship; relationship != nil {
@@ -508,30 +499,26 @@ func (scope *Scope) createJoinTable(field *StructField) {
 	if relationship := field.Relationship; relationship != nil && relationship.JoinTableHandler != nil {
 		joinTableHandler := relationship.JoinTableHandler
 		joinTable := joinTableHandler.Table(scope.db)
-		if !scope.Dialect().HasTable(scope, joinTable) {
+		if !scope.Dialect().HasTable(joinTable) {
 			toScope := &Scope{Value: reflect.New(field.Struct.Type).Interface()}
 
 			var sqlTypes, primaryKeys []string
 			for idx, fieldName := range relationship.ForeignFieldNames {
-				if field, ok := scope.Fields()[fieldName]; ok {
+				if field, ok := scope.FieldByName(fieldName); ok {
-					value := reflect.Indirect(reflect.New(field.Struct.Type))
+					foreignKeyStruct := field.clone()
-					primaryKeySqlType := field.TagSettings["TYPE"]
+					foreignKeyStruct.IsPrimaryKey = false
-					if primaryKeySqlType == "" {
+					foreignKeyStruct.TagSettings["IS_JOINTABLE_FOREIGNKEY"] = "true"
-						primaryKeySqlType = scope.Dialect().SqlTag(value, 255, false)
+					sqlTypes = append(sqlTypes, scope.Quote(relationship.ForeignDBNames[idx])+" "+scope.Dialect().DataTypeOf(foreignKeyStruct))
-					}
-					sqlTypes = append(sqlTypes, scope.Quote(relationship.ForeignDBNames[idx])+" "+primaryKeySqlType)
 					primaryKeys = append(primaryKeys, scope.Quote(relationship.ForeignDBNames[idx]))
 				}
 			}
 
 			for idx, fieldName := range relationship.AssociationForeignFieldNames {
-				if field, ok := toScope.Fields()[fieldName]; ok {
+				if field, ok := toScope.FieldByName(fieldName); ok {
-					value := reflect.Indirect(reflect.New(field.Struct.Type))
+					foreignKeyStruct := field.clone()
-					primaryKeySqlType := field.TagSettings["TYPE"]
+					foreignKeyStruct.IsPrimaryKey = false
-					if primaryKeySqlType == "" {
+					foreignKeyStruct.TagSettings["IS_JOINTABLE_FOREIGNKEY"] = "true"
-						primaryKeySqlType = scope.Dialect().SqlTag(value, 255, false)
+					sqlTypes = append(sqlTypes, scope.Quote(relationship.AssociationForeignDBNames[idx])+" "+scope.Dialect().DataTypeOf(foreignKeyStruct))
-					}
-					sqlTypes = append(sqlTypes, scope.Quote(relationship.AssociationForeignDBNames[idx])+" "+primaryKeySqlType)
 					primaryKeys = append(primaryKeys, scope.Quote(relationship.AssociationForeignDBNames[idx]))
 				}
 			}
@@ -545,10 +532,10 @@ func (scope *Scope) createJoinTable(field *StructField) {
 func (scope *Scope) createTable() *Scope {
 	var tags []string
 	var primaryKeys []string
-	var primaryKeyInColumnType bool = false
+	var primaryKeyInColumnType = false
-	for _, field := range scope.GetStructFields() {
+	for _, field := range scope.GetModelStruct().StructFields {
 		if field.IsNormal {
-			sqlTag := scope.generateSqlTag(field)
+			sqlTag := scope.Dialect().DataTypeOf(field)
 
 			// Check if the primary key constraint was specified as
 			// part of the column type. If so, we can only support
@@ -582,13 +569,6 @@ func (scope *Scope) dropTable() *Scope {
 	return scope
 }
 
-func (scope *Scope) dropTableIfExists() *Scope {
-	if scope.Dialect().HasTable(scope, scope.TableName()) {
-		scope.dropTable()
-	}
-	return scope
-}
-
 func (scope *Scope) modifyColumn(column string, typ string) {
 	scope.Raw(fmt.Sprintf("ALTER TABLE %v MODIFY %v %v", scope.QuotedTableName(), scope.Quote(column), typ)).Exec()
 }
@@ -598,13 +578,13 @@ func (scope *Scope) dropColumn(column string) {
 }
 
 func (scope *Scope) addIndex(unique bool, indexName string, column ...string) {
-	if scope.Dialect().HasIndex(scope, scope.TableName(), indexName) {
+	if scope.Dialect().HasIndex(scope.TableName(), indexName) {
 		return
 	}
 
 	var columns []string
 	for _, name := range column {
-		columns = append(columns, scope.QuoteIfPossible(name))
+		columns = append(columns, scope.quoteIfPossible(name))
 	}
 
 	sqlCreate := "CREATE INDEX"
@@ -612,31 +592,35 @@ func (scope *Scope) addIndex(unique bool, indexName string, column ...string) {
 		sqlCreate = "CREATE UNIQUE INDEX"
 	}
 
-	scope.Raw(fmt.Sprintf("%s %v ON %v(%v) %v", sqlCreate, indexName, scope.QuotedTableName(), strings.Join(columns, ", "), scope.whereSql())).Exec()
+	scope.Raw(fmt.Sprintf("%s %v ON %v(%v) %v", sqlCreate, indexName, scope.QuotedTableName(), strings.Join(columns, ", "), scope.whereSQL())).Exec()
 }
 
 func (scope *Scope) addForeignKey(field string, dest string, onDelete string, onUpdate string) {
 	var keyName = fmt.Sprintf("%s_%s_%s_foreign", scope.TableName(), field, dest)
 	keyName = regexp.MustCompile("(_*[^a-zA-Z]+_*|_+)").ReplaceAllString(keyName, "_")
+
+	if scope.Dialect().HasForeignKey(scope.TableName(), keyName) {
+		return
+	}
 	var query = `ALTER TABLE %s ADD CONSTRAINT %s FOREIGN KEY (%s) REFERENCES %s ON DELETE %s ON UPDATE %s;`
-	scope.Raw(fmt.Sprintf(query, scope.QuotedTableName(), scope.QuoteIfPossible(keyName), scope.QuoteIfPossible(field), dest, onDelete, onUpdate)).Exec()
+	scope.Raw(fmt.Sprintf(query, scope.QuotedTableName(), scope.quoteIfPossible(keyName), scope.quoteIfPossible(field), dest, onDelete, onUpdate)).Exec()
 }
 
 func (scope *Scope) removeIndex(indexName string) {
-	scope.Dialect().RemoveIndex(scope, indexName)
+	scope.Dialect().RemoveIndex(scope.TableName(), indexName)
 }
 
 func (scope *Scope) autoMigrate() *Scope {
 	tableName := scope.TableName()
 	quotedTableName := scope.QuotedTableName()
 
-	if !scope.Dialect().HasTable(scope, tableName) {
+	if !scope.Dialect().HasTable(tableName) {
 		scope.createTable()
 	} else {
-		for _, field := range scope.GetStructFields() {
+		for _, field := range scope.GetModelStruct().StructFields {
-			if !scope.Dialect().HasColumn(scope, tableName, field.DBName) {
+			if !scope.Dialect().HasColumn(tableName, field.DBName) {
 				if field.IsNormal {
-					sqlTag := scope.generateSqlTag(field)
+					sqlTag := scope.Dialect().DataTypeOf(field)
 					scope.Raw(fmt.Sprintf("ALTER TABLE %v ADD %v %v;", quotedTableName, scope.Quote(field.DBName), sqlTag)).Exec()
 				}
 			}

scope_utils.go

@@ -0,0 +1,67 @@
+package gorm
+
+import "reflect"
+
+func (scope *Scope) getColumnAsArray(columns []string, values ...interface{}) (results [][]interface{}) {
+	for _, value := range values {
+		indirectValue := reflect.ValueOf(value)
+		for indirectValue.Kind() == reflect.Ptr {
+			indirectValue = indirectValue.Elem()
+		}
+
+		switch indirectValue.Kind() {
+		case reflect.Slice:
+			for i := 0; i < indirectValue.Len(); i++ {
+				var result []interface{}
+				var object = indirect(indirectValue.Index(i))
+				for _, column := range columns {
+					result = append(result, object.FieldByName(column).Interface())
+				}
+				results = append(results, result)
+			}
+		case reflect.Struct:
+			var result []interface{}
+			for _, column := range columns {
+				result = append(result, indirectValue.FieldByName(column).Interface())
+			}
+			results = append(results, result)
+		}
+	}
+	return
+}
+
+func (scope *Scope) getColumnAsScope(column string) *Scope {
+	indirectScopeValue := scope.IndirectValue()
+
+	switch indirectScopeValue.Kind() {
+	case reflect.Slice:
+		if fieldStruct, ok := scope.GetModelStruct().ModelType.FieldByName(column); ok {
+			fieldType := fieldStruct.Type
+			if fieldType.Kind() == reflect.Slice || fieldType.Kind() == reflect.Ptr {
+				fieldType = fieldType.Elem()
+			}
+
+			results := reflect.New(reflect.SliceOf(reflect.PtrTo(fieldType))).Elem()
+
+			for i := 0; i < indirectScopeValue.Len(); i++ {
+				result := indirect(indirect(indirectScopeValue.Index(i)).FieldByName(column))
+
+				if result.Kind() == reflect.Slice {
+					for j := 0; j < result.Len(); j++ {
+						if elem := result.Index(j); elem.CanAddr() {
+							results = reflect.Append(results, elem.Addr())
+						}
+					}
+				} else if result.CanAddr() {
+					results = reflect.Append(results, result.Addr())
+				}
+			}
+			return scope.New(results.Interface())
+		}
+	case reflect.Struct:
+		if field := indirectScopeValue.FieldByName(column); field.CanAddr() {
+			return scope.New(field.Addr().Interface())
+		}
+	}
+	return nil
+}

search.go

@@ -8,15 +8,15 @@ type search struct {
 	orConditions     []map[string]interface{}
 	notConditions    []map[string]interface{}
 	havingConditions []map[string]interface{}
+	joinConditions   []map[string]interface{}
 	initAttrs        []interface{}
 	assignAttrs      []interface{}
 	selects          map[string]interface{}
 	omits            []string
 	orders           []string
-	joins            string
 	preload          []searchPreload
-	offset           string
+	offset           int
-	limit            string
+	limit            int
 	group            string
 	tableName        string
 	raw              bool
@@ -82,18 +82,18 @@ func (s *search) Omit(columns ...string) *search {
 	return s
 }
 
-func (s *search) Limit(value interface{}) *search {
+func (s *search) Limit(limit int) *search {
-	s.limit = s.getInterfaceAsSql(value)
+	s.limit = limit
 	return s
 }
 
-func (s *search) Offset(value interface{}) *search {
+func (s *search) Offset(offset int) *search {
-	s.offset = s.getInterfaceAsSql(value)
+	s.offset = offset
 	return s
 }
 
 func (s *search) Group(query string) *search {
-	s.group = s.getInterfaceAsSql(query)
+	s.group = s.getInterfaceAsSQL(query)
 	return s
 }
 
@@ -102,8 +102,8 @@ func (s *search) Having(query string, values ...interface{}) *search {
 	return s
 }
 
-func (s *search) Joins(query string) *search {
+func (s *search) Joins(query string, values ...interface{}) *search {
-	s.joins = query
+	s.joinConditions = append(s.joinConditions, map[string]interface{}{"query": query, "args": values})
 	return s
 }
 
@@ -134,12 +134,12 @@ func (s *search) Table(name string) *search {
 	return s
 }
 
-func (s *search) getInterfaceAsSql(value interface{}) (str string) {
+func (s *search) getInterfaceAsSQL(value interface{}) (str string) {
 	switch value.(type) {
 	case string, int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64:
 		str = fmt.Sprintf("%v", value)
 	default:
-		s.db.AddError(InvalidSql)
+		s.db.AddError(ErrInvalidSQL)
 	}
 
 	if str == "-1" {

sqlite3.go

@@ -1,84 +0,0 @@
-package gorm
-
-import (
-	"fmt"
-	"reflect"
-	"time"
-)
-
-type sqlite3 struct {
-	commonDialect
-}
-
-func (sqlite3) SqlTag(value reflect.Value, size int, autoIncrease bool) string {
-	switch value.Kind() {
-	case reflect.Bool:
-		return "bool"
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
-		if autoIncrease {
-			return "integer primary key autoincrement"
-		}
-		return "integer"
-	case reflect.Int64, reflect.Uint64:
-		if autoIncrease {
-			return "integer primary key autoincrement"
-		}
-		return "bigint"
-	case reflect.Float32, reflect.Float64:
-		return "real"
-	case reflect.String:
-		if size > 0 && size < 65532 {
-			return fmt.Sprintf("varchar(%d)", size)
-		}
-		return "text"
-	case reflect.Struct:
-		if _, ok := value.Interface().(time.Time); ok {
-			return "datetime"
-		}
-	default:
-		if _, ok := value.Interface().([]byte); ok {
-			return "blob"
-		}
-	}
-	panic(fmt.Sprintf("invalid sql type %s (%s) for sqlite3", value.Type().Name(), value.Kind().String()))
-}
-
-func (s sqlite3) HasTable(scope *Scope, tableName string) bool {
-	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM sqlite_master WHERE type='table' AND name=?", tableName)
-	return count > 0
-}
-
-func (s sqlite3) HasColumn(scope *Scope, tableName string, columnName string) bool {
-	var count int
-	s.RawScanInt(scope, &count, fmt.Sprintf("SELECT count(*) FROM sqlite_master WHERE tbl_name = ? AND (sql LIKE '%%(\"%v\" %%' OR sql LIKE '%%,\"%v\" %%' OR sql LIKE '%%, \"%v\" %%' OR sql LIKE '%%( %v %%' OR sql LIKE '%%, %v %%' OR sql LIKE '%%,%v %%');\n", columnName, columnName, columnName, columnName, columnName, columnName), tableName)
-	return count > 0
-}
-
-func (s sqlite3) HasIndex(scope *Scope, tableName string, indexName string) bool {
-	var count int
-	s.RawScanInt(scope, &count, fmt.Sprintf("SELECT count(*) FROM sqlite_master WHERE tbl_name = ? AND sql LIKE '%%INDEX %v ON%%'", indexName), tableName)
-	return count > 0
-}
-
-func (sqlite3) RemoveIndex(scope *Scope, indexName string) {
-	scope.Err(scope.NewDB().Exec(fmt.Sprintf("DROP INDEX %v", indexName)).Error)
-}
-
-func (sqlite3) CurrentDatabase(scope *Scope) (name string) {
-	var (
-		ifaces   = make([]interface{}, 3)
-		pointers = make([]*string, 3)
-		i        int
-	)
-	for i = 0; i < 3; i++ {
-		ifaces[i] = &pointers[i]
-	}
-	if err := scope.NewDB().Raw("PRAGMA database_list").Row().Scan(ifaces...); scope.Err(err) != nil {
-		return
-	}
-	if pointers[1] != nil {
-		name = *pointers[1]
-	}
-	return
-}

structs_test.go

@@ -42,9 +42,9 @@ type CreditCard struct {
 	ID        int8
 	Number    string
 	UserId    sql.NullInt64
-	CreatedAt time.Time
+	CreatedAt time.Time `sql:"not null"`
 	UpdatedAt time.Time
-	DeletedAt time.Time
+	DeletedAt *time.Time
 }
 
 type Email struct {
@@ -62,7 +62,7 @@ type Address struct {
 	Post      string
 	CreatedAt time.Time
 	UpdatedAt time.Time
-	DeletedAt time.Time
+	DeletedAt *time.Time
 }
 
 type Language struct {

update_test.go

@@ -71,13 +71,14 @@ func TestUpdate(t *testing.T) {
 	}
 
 	DB.First(&product4, product4.Id)
+	updatedAt4 := product4.UpdatedAt
 	DB.Model(&product4).Update("price", gorm.Expr("price + ? - ?", 100, 50))
 	var product5 Product
 	DB.First(&product5, product4.Id)
 	if product5.Price != product4.Price+100-50 {
 		t.Errorf("Update with expression")
 	}
-	if product5.UpdatedAt.Format(time.RFC3339Nano) == product4.UpdatedAt.Format(time.RFC3339Nano) {
+	if product4.UpdatedAt.Format(time.RFC3339Nano) == updatedAt4.Format(time.RFC3339Nano) {
 		t.Errorf("Update with expression should update UpdatedAt")
 	}
 }
@@ -170,13 +171,15 @@ func TestUpdates(t *testing.T) {
 		t.Errorf("product2's code should be updated")
 	}
 
+	updatedAt4 := product4.UpdatedAt
 	DB.Model(&product4).Updates(map[string]interface{}{"price": gorm.Expr("price + ?", 100)})
 	var product5 Product
 	DB.First(&product5, product4.Id)
 	if product5.Price != product4.Price+100 {
 		t.Errorf("Updates with expression")
 	}
-	if product5.UpdatedAt.Format(time.RFC3339Nano) == product4.UpdatedAt.Format(time.RFC3339Nano) {
+	// product4's UpdatedAt will be reset when updating
+	if product4.UpdatedAt.Format(time.RFC3339Nano) == updatedAt4.Format(time.RFC3339Nano) {
 		t.Errorf("Updates with expression should update UpdatedAt")
 	}
 }
@@ -419,3 +422,32 @@ func TestUpdateColumnsSkipsAssociations(t *testing.T) {
 		t.Errorf("Expected user's BillingAddress.Address1=%s to remain unchanged after UpdateColumns invocation, but BillingAddress.Address1=%s", address1, freshUser.BillingAddress.Address1)
 	}
 }
+
+func TestUpdatesWithBlankValues(t *testing.T) {
+	product := Product{Code: "product1", Price: 10}
+	DB.Save(&product)
+
+	DB.Model(&Product{Id: product.Id}).Updates(&Product{Price: 100})
+
+	var product1 Product
+	DB.First(&product1, product.Id)
+
+	if product1.Code != "product1" || product1.Price != 100 {
+		t.Errorf("product's code should not be updated")
+	}
+}
+
+func TestUpdateDecodeVirtualAttributes(t *testing.T) {
+	var user = User{
+		Name:     "jinzhu",
+		IgnoreMe: 88,
+	}
+
+	DB.Save(&user)
+
+	DB.Model(&user).Updates(User{Name: "jinzhu2", IgnoreMe: 100})
+
+	if user.IgnoreMe != 100 {
+		t.Errorf("should decode virtual attributes to struct, so it could be used in callbacks")
+	}
+}

utils.go

@@ -2,10 +2,26 @@ package gorm
 
 import (
 	"bytes"
+	"database/sql/driver"
+	"fmt"
+	"reflect"
+	"regexp"
+	"runtime"
 	"strings"
 	"sync"
+	"time"
 )
 
+// NowFunc returns current time, this function is exported in order to be able
+// to give the flexibility to the developer to customize it according to their
+// needs, e.g:
+//    gorm.NowFunc = func() time.Time {
+//      return time.Now().UTC()
+//    }
+var NowFunc = func() time.Time {
+	return time.Now()
+}
+
 // Copied from golint
 var commonInitialisms = []string{"API", "ASCII", "CPU", "CSS", "DNS", "EOF", "GUID", "HTML", "HTTP", "HTTPS", "ID", "IP", "JSON", "LHS", "QPS", "RAM", "RHS", "RPC", "SLA", "SMTP", "SSH", "TLS", "TTL", "UI", "UID", "UUID", "URI", "URL", "UTF8", "VM", "XML", "XSRF", "XSS"}
 var commonInitialismsReplacer *strings.Replacer
@@ -41,30 +57,239 @@ func newSafeMap() *safeMap {
 
 var smap = newSafeMap()
 
+type strCase bool
+
+const (
+	lower strCase = false
+	upper strCase = true
+)
+
+// ToDBName convert string to db name
 func ToDBName(name string) string {
 	if v := smap.Get(name); v != "" {
 		return v
 	}
 
-	value := commonInitialismsReplacer.Replace(name)
+	if name == "" {
-	buf := bytes.NewBufferString("")
+		return ""
-	for i, v := range value {
+	}
-		if i > 0 && v >= 'A' && v <= 'Z' {
+
+	var (
+		value                        = commonInitialismsReplacer.Replace(name)
+		buf                          = bytes.NewBufferString("")
+		lastCase, currCase, nextCase strCase
+	)
+
+	for i, v := range value[:len(value)-1] {
+		nextCase = value[i+1] >= 'A' && value[i+1] <= 'Z'
+		if i > 0 {
+			if currCase == upper {
+				if lastCase == upper && nextCase == upper {
+					buf.WriteRune(v)
+				} else {
+					if value[i-1] != '_' && value[i+1] != '_' {
 						buf.WriteRune('_')
 					}
 					buf.WriteRune(v)
 				}
+			} else {
+				buf.WriteRune(v)
+			}
+		} else {
+			currCase = upper
+			buf.WriteRune(v)
+		}
+		lastCase = currCase
+		currCase = nextCase
+	}
+
+	buf.WriteByte(value[len(value)-1])
 
 	s := strings.ToLower(buf.String())
 	smap.Set(name, s)
 	return s
 }
 
+// SQL expression
 type expr struct {
 	expr string
 	args []interface{}
 }
 
+// Expr generate raw SQL expression, for example:
+//     DB.Model(&product).Update("price", gorm.Expr("price * ? + ?", 2, 100))
 func Expr(expression string, args ...interface{}) *expr {
 	return &expr{expr: expression, args: args}
 }
+
+func indirect(reflectValue reflect.Value) reflect.Value {
+	for reflectValue.Kind() == reflect.Ptr {
+		reflectValue = reflectValue.Elem()
+	}
+	return reflectValue
+}
+
+func toQueryMarks(primaryValues [][]interface{}) string {
+	var results []string
+
+	for _, primaryValue := range primaryValues {
+		var marks []string
+		for _ = range primaryValue {
+			marks = append(marks, "?")
+		}
+
+		if len(marks) > 1 {
+			results = append(results, fmt.Sprintf("(%v)", strings.Join(marks, ",")))
+		} else {
+			results = append(results, strings.Join(marks, ""))
+		}
+	}
+	return strings.Join(results, ",")
+}
+
+func toQueryCondition(scope *Scope, columns []string) string {
+	var newColumns []string
+	for _, column := range columns {
+		newColumns = append(newColumns, scope.Quote(column))
+	}
+
+	if len(columns) > 1 {
+		return fmt.Sprintf("(%v)", strings.Join(newColumns, ","))
+	}
+	return strings.Join(newColumns, ",")
+}
+
+func toQueryValues(values [][]interface{}) (results []interface{}) {
+	for _, value := range values {
+		for _, v := range value {
+			results = append(results, v)
+		}
+	}
+	return
+}
+
+func fileWithLineNum() string {
+	for i := 2; i < 15; i++ {
+		_, file, line, ok := runtime.Caller(i)
+		if ok && (!regexp.MustCompile(`jinzhu/gorm/.*.go`).MatchString(file) || regexp.MustCompile(`jinzhu/gorm/.*test.go`).MatchString(file)) {
+			return fmt.Sprintf("%v:%v", file, line)
+		}
+	}
+	return ""
+}
+
+func isBlank(value reflect.Value) bool {
+	return reflect.DeepEqual(value.Interface(), reflect.Zero(value.Type()).Interface())
+}
+
+func toSearchableMap(attrs ...interface{}) (result interface{}) {
+	if len(attrs) > 1 {
+		if str, ok := attrs[0].(string); ok {
+			result = map[string]interface{}{str: attrs[1]}
+		}
+	} else if len(attrs) == 1 {
+		if attr, ok := attrs[0].(map[string]interface{}); ok {
+			result = attr
+		}
+
+		if attr, ok := attrs[0].(interface{}); ok {
+			result = attr
+		}
+	}
+	return
+}
+
+func convertInterfaceToMap(values interface{}) map[string]interface{} {
+	attrs := map[string]interface{}{}
+
+	switch value := values.(type) {
+	case map[string]interface{}:
+		return value
+	case []interface{}:
+		for _, v := range value {
+			for key, value := range convertInterfaceToMap(v) {
+				attrs[key] = value
+			}
+		}
+	case interface{}:
+		reflectValue := reflect.ValueOf(values)
+
+		switch reflectValue.Kind() {
+		case reflect.Map:
+			for _, key := range reflectValue.MapKeys() {
+				attrs[ToDBName(key.Interface().(string))] = reflectValue.MapIndex(key).Interface()
+			}
+		default:
+			for _, field := range (&Scope{Value: values}).Fields() {
+				if !field.IsBlank {
+					attrs[field.DBName] = field.Field.Interface()
+				}
+			}
+		}
+	}
+	return attrs
+}
+
+func equalAsString(a interface{}, b interface{}) bool {
+	return toString(a) == toString(b)
+}
+
+func toString(str interface{}) string {
+	if values, ok := str.([]interface{}); ok {
+		var results []string
+		for _, value := range values {
+			results = append(results, toString(value))
+		}
+		return strings.Join(results, "_")
+	} else if bytes, ok := str.([]byte); ok {
+		return string(bytes)
+	} else if reflectValue := reflect.Indirect(reflect.ValueOf(str)); reflectValue.IsValid() {
+		return fmt.Sprintf("%v", reflectValue.Interface())
+	}
+	return ""
+}
+
+func makeSlice(elemType reflect.Type) interface{} {
+	if elemType.Kind() == reflect.Slice {
+		elemType = elemType.Elem()
+	}
+	sliceType := reflect.SliceOf(elemType)
+	slice := reflect.New(sliceType)
+	slice.Elem().Set(reflect.MakeSlice(sliceType, 0, 0))
+	return slice.Interface()
+}
+
+func strInSlice(a string, list []string) bool {
+	for _, b := range list {
+		if b == a {
+			return true
+		}
+	}
+	return false
+}
+
+// getValueFromFields return given fields's value
+func getValueFromFields(value reflect.Value, fieldNames []string) (results []interface{}) {
+	// If value is a nil pointer, Indirect returns a zero Value!
+	// Therefor we need to check for a zero value,
+	// as FieldByName could panic
+	if indirectValue := reflect.Indirect(value); indirectValue.IsValid() {
+		for _, fieldName := range fieldNames {
+			if fieldValue := indirectValue.FieldByName(fieldName); fieldValue.IsValid() {
+				result := fieldValue.Interface()
+				if r, ok := result.(driver.Valuer); ok {
+					result, _ = r.Value()
+				}
+				results = append(results, result)
+			}
+		}
+	}
+	return
+}
+
+func addExtraSpaceIfExist(str string) string {
+	if str != "" {
+		return " " + str
+	}
+	return ""
+}

utils_private.go

@@ -1,98 +0,0 @@
-package gorm
-
-import (
-	"fmt"
-	"reflect"
-	"regexp"
-	"runtime"
-	"strings"
-)
-
-func fileWithLineNum() string {
-	for i := 2; i < 15; i++ {
-		_, file, line, ok := runtime.Caller(i)
-		if ok && (!regexp.MustCompile(`jinzhu/gorm/.*.go`).MatchString(file) || regexp.MustCompile(`jinzhu/gorm/.*test.go`).MatchString(file)) {
-			return fmt.Sprintf("%v:%v", file, line)
-		}
-	}
-	return ""
-}
-
-func isBlank(value reflect.Value) bool {
-	return reflect.DeepEqual(value.Interface(), reflect.Zero(value.Type()).Interface())
-}
-
-func toSearchableMap(attrs ...interface{}) (result interface{}) {
-	if len(attrs) > 1 {
-		if str, ok := attrs[0].(string); ok {
-			result = map[string]interface{}{str: attrs[1]}
-		}
-	} else if len(attrs) == 1 {
-		if attr, ok := attrs[0].(map[string]interface{}); ok {
-			result = attr
-		}
-
-		if attr, ok := attrs[0].(interface{}); ok {
-			result = attr
-		}
-	}
-	return
-}
-
-func convertInterfaceToMap(values interface{}) map[string]interface{} {
-	attrs := map[string]interface{}{}
-
-	switch value := values.(type) {
-	case map[string]interface{}:
-		for k, v := range value {
-			attrs[ToDBName(k)] = v
-		}
-	case []interface{}:
-		for _, v := range value {
-			for key, value := range convertInterfaceToMap(v) {
-				attrs[key] = value
-			}
-		}
-	case interface{}:
-		reflectValue := reflect.ValueOf(values)
-
-		switch reflectValue.Kind() {
-		case reflect.Map:
-			for _, key := range reflectValue.MapKeys() {
-				attrs[ToDBName(key.Interface().(string))] = reflectValue.MapIndex(key).Interface()
-			}
-		default:
-			scope := Scope{Value: values}
-			for _, field := range scope.Fields() {
-				if !field.IsBlank && !field.IsIgnored {
-					attrs[field.DBName] = field.Field.Interface()
-				}
-			}
-		}
-	}
-	return attrs
-}
-
-func toString(str interface{}) string {
-	if values, ok := str.([]interface{}); ok {
-		var results []string
-		for _, value := range values {
-			results = append(results, toString(value))
-		}
-		return strings.Join(results, "_")
-	} else if bytes, ok := str.([]byte); ok {
-		return string(bytes)
-	} else if reflectValue := reflect.Indirect(reflect.ValueOf(str)); reflectValue.IsValid() {
-		return fmt.Sprintf("%v", reflectValue.Interface())
-	}
-	return ""
-}
-
-func strInSlice(a string, list []string) bool {
-	for _, b := range list {
-		if b == a {
-			return true
-		}
-	}
-	return false
-}

utils_test.go

@@ -0,0 +1,30 @@
+package gorm_test
+
+import (
+	"testing"
+
+	"github.com/jinzhu/gorm"
+)
+
+func TestToDBNameGenerateFriendlyName(t *testing.T) {
+	var maps = map[string]string{
+		"":                          "",
+		"ThisIsATest":               "this_is_a_test",
+		"PFAndESI":                  "pf_and_esi",
+		"AbcAndJkl":                 "abc_and_jkl",
+		"EmployeeID":                "employee_id",
+		"SKU_ID":                    "sku_id",
+		"HTTPAndSMTP":               "http_and_smtp",
+		"HTTPServerHandlerForURLID": "http_server_handler_for_url_id",
+		"UUID":     "uuid",
+		"HTTPURL":  "http_url",
+		"HTTP_URL": "http_url",
+		"ThisIsActuallyATestSoWeMayBeAbleToUseThisCodeInGormPackageAlsoIdCanBeUsedAtTheEndAsID": "this_is_actually_a_test_so_we_may_be_able_to_use_this_code_in_gorm_package_also_id_can_be_used_at_the_end_as_id",
+	}
+
+	for key, value := range maps {
+		if gorm.ToDBName(key) != value {
+			t.Errorf("%v ToDBName should equal %v, but got %v", key, value, gorm.ToDBName(key))
+		}
+	}
+}