diff --git a/callback.go b/callback.go
index d2f8e2bd..ac84b930 100644
--- a/callback.go
+++ b/callback.go
@@ -249,6 +249,14 @@ func handleDefaultValue(scope *Scope, field *Field) string {
 					return escapeIfNeeded(scope, defaultValue)
 				}
 			}
+			/*
+				case reflect.String:
+					if defaultValue != field.Field.String() {
+						return escapeIfNeeded(scope, fmt.Sprintf("%s", field.Field.String()))
+					} else {
+						return escapeIfNeeded(scope, defaultValue)
+					}
+			*/
 		default:
 			return escapeIfNeeded(scope, defaultValue)
 		}
diff --git a/callback_query.go b/callback_query.go
index 387e813d..5473f232 100644
--- a/callback_query.go
+++ b/callback_query.go
@@ -71,7 +71,9 @@ func Query(scope *Scope) {
 					if field.Field.Kind() == reflect.Ptr {
 						values[index] = field.Field.Addr().Interface()
 					} else {
-						values[index] = reflect.New(reflect.PtrTo(field.Field.Type())).Interface()
+						reflectValue := reflect.New(reflect.PtrTo(field.Struct.Type))
+						reflectValue.Elem().Set(field.Field.Addr())
+						values[index] = reflectValue.Interface()
 					}
 				} else {
 					var value interface{}
diff --git a/field.go b/field.go
index a56dbe51..db1fdd8f 100644
--- a/field.go
+++ b/field.go
@@ -3,6 +3,7 @@ package gorm
 import (
 	"database/sql"
 	"errors"
+	"fmt"
 	"reflect"
 )
 
@@ -44,7 +45,7 @@ func (field *Field) Set(value interface{}) error {
 		if reflectValue.Type().ConvertibleTo(field.Field.Type()) {
 			field.Field.Set(reflectValue.Convert(field.Field.Type()))
 		} else {
-			return errors.New("could not convert argument")
+			return fmt.Errorf("could not convert argument of field %s from %s to %s", field.Name, reflectValue.Type(), field.Field.Type())
 		}
 	}
 
@@ -61,10 +62,12 @@ func (scope *Scope) Fields() map[string]*Field {
 		indirectValue := scope.IndirectValue()
 		isStruct := indirectValue.Kind() == reflect.Struct
 		for _, structField := range modelStruct.StructFields {
-			if isStruct {
-				fields[structField.DBName] = getField(indirectValue, structField)
-			} else {
-				fields[structField.DBName] = &Field{StructField: structField, IsBlank: true}
+			if field, ok := fields[structField.DBName]; !ok || field.IsIgnored {
+				if isStruct {
+					fields[structField.DBName] = getField(indirectValue, structField)
+				} else {
+					fields[structField.DBName] = &Field{StructField: structField, IsBlank: true}
+				}
 			}
 		}
 
diff --git a/model_struct.go b/model_struct.go
index 4ea821d6..97d145b6 100644
--- a/model_struct.go
+++ b/model_struct.go
@@ -10,7 +10,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/qor/inflection"
+	"github.com/jinzhu/inflection"
 )
 
 var DefaultTableNameHandler = func(db *DB, defaultTableName string) string {
@@ -149,24 +149,25 @@ func (scope *Scope) GetModelStruct() *ModelStruct {
 
 			if fieldStruct.Tag.Get("sql") == "-" {
 				field.IsIgnored = true
-			} else {
-				sqlSettings := parseTagSetting(field.Tag.Get("sql"))
-				gormSettings := parseTagSetting(field.Tag.Get("gorm"))
-				if _, ok := gormSettings["PRIMARY_KEY"]; ok {
-					field.IsPrimaryKey = true
-					modelStruct.PrimaryFields = append(modelStruct.PrimaryFields, field)
-				}
-
-				if _, ok := sqlSettings["DEFAULT"]; ok {
-					field.HasDefaultValue = true
-				}
-
-				if value, ok := gormSettings["COLUMN"]; ok {
-					field.DBName = value
-				} else {
-					field.DBName = ToDBName(fieldStruct.Name)
-				}
 			}
+
+			sqlSettings := parseTagSetting(field.Tag.Get("sql"))
+			gormSettings := parseTagSetting(field.Tag.Get("gorm"))
+			if _, ok := gormSettings["PRIMARY_KEY"]; ok {
+				field.IsPrimaryKey = true
+				modelStruct.PrimaryFields = append(modelStruct.PrimaryFields, field)
+			}
+
+			if _, ok := sqlSettings["DEFAULT"]; ok {
+				field.HasDefaultValue = true
+			}
+
+			if value, ok := gormSettings["COLUMN"]; ok {
+				field.DBName = value
+			} else {
+				field.DBName = ToDBName(fieldStruct.Name)
+			}
+
 			fields = append(fields, field)
 		}
 	}
diff --git a/preload.go b/preload.go
index 2d1aed2f..417a0d8c 100644
--- a/preload.go
+++ b/preload.go
@@ -209,6 +209,7 @@ func (scope *Scope) handleManyToManyPreload(field *Field, conditions []interface
 	}
 
 	db := scope.NewDB().Table(scope.New(reflect.New(destType).Interface()).TableName()).Select("*")
+
 	preloadJoinDB := joinTableHandler.JoinWith(joinTableHandler, db, scope.Value)
 
 	if len(conditions) > 0 {
@@ -228,13 +229,15 @@ func (scope *Scope) handleManyToManyPreload(field *Field, conditions []interface
 
 		fields := scope.New(elem.Addr().Interface()).Fields()
 
+		var foundFields = map[string]bool{}
 		for index, column := range columns {
-			if field, ok := fields[column]; ok {
+			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
@@ -245,14 +248,16 @@ func (scope *Scope) handleManyToManyPreload(field *Field, conditions []interface
 
 		var sourceKey []interface{}
 
+		var scannedFields = map[string]bool{}
 		for index, column := range columns {
 			value := values[index]
-			if field, ok := fields[column]; ok {
+			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{})))
 			}
diff --git a/scope_private.go b/scope_private.go
index d5aacfdb..4fd7149d 100644
--- a/scope_private.go
+++ b/scope_private.go
@@ -492,12 +492,13 @@ func (scope *Scope) createJoinTable(field *StructField) {
 		if !scope.Dialect().HasTable(scope, joinTable) {
 			toScope := &Scope{Value: reflect.New(field.Struct.Type).Interface()}
 
-			var sqlTypes []string
+			var sqlTypes, primaryKeys []string
 			for idx, fieldName := range relationship.ForeignFieldNames {
 				if field, ok := scope.Fields()[fieldName]; ok {
 					value := reflect.Indirect(reflect.New(field.Struct.Type))
 					primaryKeySqlType := scope.Dialect().SqlTag(value, 255, false)
 					sqlTypes = append(sqlTypes, scope.Quote(relationship.ForeignDBNames[idx])+" "+primaryKeySqlType)
+					primaryKeys = append(primaryKeys, scope.Quote(relationship.ForeignDBNames[idx]))
 				}
 			}
 
@@ -506,9 +507,11 @@ func (scope *Scope) createJoinTable(field *StructField) {
 					value := reflect.Indirect(reflect.New(field.Struct.Type))
 					primaryKeySqlType := scope.Dialect().SqlTag(value, 255, false)
 					sqlTypes = append(sqlTypes, scope.Quote(relationship.AssociationForeignDBNames[idx])+" "+primaryKeySqlType)
+					primaryKeys = append(primaryKeys, scope.Quote(relationship.AssociationForeignDBNames[idx]))
 				}
 			}
-			scope.Err(scope.NewDB().Exec(fmt.Sprintf("CREATE TABLE %v (%v) %s", scope.Quote(joinTable), strings.Join(sqlTypes, ","), scope.getTableOptions())).Error)
+
+			scope.Err(scope.NewDB().Exec(fmt.Sprintf("CREATE TABLE %v (%v, PRIMARY KEY (%v)) %s", scope.Quote(joinTable), strings.Join(sqlTypes, ","), strings.Join(primaryKeys, ","), scope.getTableOptions())).Error)
 		}
 		scope.NewDB().Table(joinTable).AutoMigrate(joinTableHandler)
 	}