Enhance migrator Columntype interface (#5088)

* Update Migrator ColumnType interface

* Update MigrateColumn Test

* Upgrade test drivers

* Fix typo

migrator.go

@@ -1,6 +1,8 @@
 package gorm
 
 import (
+	"reflect"
+
 	"gorm.io/gorm/clause"
 	"gorm.io/gorm/schema"
 )
@@ -33,14 +35,23 @@ type ViewOption struct {
 	Query       *DB
 }
 
+// ColumnType column type interface
 type ColumnType interface {
 	Name() string
-	DatabaseTypeName() string
+	DatabaseTypeName() string                 // varchar
+	ColumnType() (columnType string, ok bool) // varchar(64)
+	PrimaryKey() (isPrimaryKey bool, ok bool)
+	AutoIncrement() (isAutoIncrement bool, ok bool)
 	Length() (length int64, ok bool)
 	DecimalSize() (precision int64, scale int64, ok bool)
 	Nullable() (nullable bool, ok bool)
+	Unique() (unique bool, ok bool)
+	ScanType() reflect.Type
+	Comment() (value string, ok bool)
+	DefaultValue() (value string, ok bool)
 }
 
+// Migrator migrator interface
 type Migrator interface {
 	// AutoMigrate
 	AutoMigrate(dst ...interface{}) error

migrator/column_type.go

@@ -0,0 +1,107 @@
+package migrator
+
+import (
+	"database/sql"
+	"reflect"
+)
+
+// ColumnType column type implements ColumnType interface
+type ColumnType struct {
+	SQLColumnType      *sql.ColumnType
+	NameValue          sql.NullString
+	DataTypeValue      sql.NullString
+	ColumnTypeValue    sql.NullString
+	PrimayKeyValue     sql.NullBool
+	UniqueValue        sql.NullBool
+	AutoIncrementValue sql.NullBool
+	LengthValue        sql.NullInt64
+	DecimalSizeValue   sql.NullInt64
+	ScaleValue         sql.NullInt64
+	NullableValue      sql.NullBool
+	ScanTypeValue      reflect.Type
+	CommentValue       sql.NullString
+	DefaultValueValue  sql.NullString
+}
+
+// Name returns the name or alias of the column.
+func (ct ColumnType) Name() string {
+	if ct.NameValue.Valid {
+		return ct.NameValue.String
+	}
+	return ct.SQLColumnType.Name()
+}
+
+// DatabaseTypeName returns the database system name of the column type. If an empty
+// string is returned, then the driver type name is not supported.
+// Consult your driver documentation for a list of driver data types. Length specifiers
+// are not included.
+// Common type names include "VARCHAR", "TEXT", "NVARCHAR", "DECIMAL", "BOOL",
+// "INT", and "BIGINT".
+func (ct ColumnType) DatabaseTypeName() string {
+	if ct.DataTypeValue.Valid {
+		return ct.DataTypeValue.String
+	}
+	return ct.SQLColumnType.DatabaseTypeName()
+}
+
+// ColumnType returns the database type of the column. lke `varchar(16)`
+func (ct ColumnType) ColumnType() (columnType string, ok bool) {
+	return ct.ColumnTypeValue.String, ct.ColumnTypeValue.Valid
+}
+
+// PrimaryKey returns the column is primary key or not.
+func (ct ColumnType) PrimaryKey() (isPrimaryKey bool, ok bool) {
+	return ct.PrimayKeyValue.Bool, ct.PrimayKeyValue.Valid
+}
+
+// AutoIncrement returns the column is auto increment or not.
+func (ct ColumnType) AutoIncrement() (isAutoIncrement bool, ok bool) {
+	return ct.AutoIncrementValue.Bool, ct.AutoIncrementValue.Valid
+}
+
+// Length returns the column type length for variable length column types
+func (ct ColumnType) Length() (length int64, ok bool) {
+	if ct.LengthValue.Valid {
+		return ct.LengthValue.Int64, true
+	}
+	return ct.SQLColumnType.Length()
+}
+
+// DecimalSize returns the scale and precision of a decimal type.
+func (ct ColumnType) DecimalSize() (precision int64, scale int64, ok bool) {
+	if ct.DecimalSizeValue.Valid {
+		return ct.DecimalSizeValue.Int64, ct.ScaleValue.Int64, true
+	}
+	return ct.SQLColumnType.DecimalSize()
+}
+
+// Nullable reports whether the column may be null.
+func (ct ColumnType) Nullable() (nullable bool, ok bool) {
+	if ct.NullableValue.Valid {
+		return ct.NullableValue.Bool, true
+	}
+	return ct.SQLColumnType.Nullable()
+}
+
+// Unique reports whether the column may be unique.
+func (ct ColumnType) Unique() (unique bool, ok bool) {
+	return ct.UniqueValue.Bool, ct.UniqueValue.Valid
+}
+
+// ScanType returns a Go type suitable for scanning into using Rows.Scan.
+func (ct ColumnType) ScanType() reflect.Type {
+	if ct.ScanTypeValue != nil {
+		return ct.ScanTypeValue
+	}
+	return ct.SQLColumnType.ScanType()
+}
+
+// Comment returns the comment of current column.
+func (ct ColumnType) Comment() (value string, ok bool) {
+	return ct.CommentValue.String, ct.CommentValue.Valid
+}
+
+// DefaultValue returns the default value of current column.
+func (ct ColumnType) DefaultValue() (value string, ok bool) {
+	return ct.DefaultValueValue.String, ct.DefaultValueValue.Valid
+}

migrator/migrator.go

@@ -30,10 +30,12 @@ type Config struct {
 	gorm.Dialector
 }
 
+// GormDataTypeInterface gorm data type interface
 type GormDataTypeInterface interface {
 	GormDBDataType(*gorm.DB, *schema.Field) string
 }
 
+// RunWithValue run migration with statement value
 func (m Migrator) RunWithValue(value interface{}, fc func(*gorm.Statement) error) error {
 	stmt := &gorm.Statement{DB: m.DB}
 	if m.DB.Statement != nil {
@@ -50,6 +52,7 @@ func (m Migrator) RunWithValue(value interface{}, fc func(*gorm.Statement) error
 	return fc(stmt)
 }
 
+// DataTypeOf return field's db data type
 func (m Migrator) DataTypeOf(field *schema.Field) string {
 	fieldValue := reflect.New(field.IndirectFieldType)
 	if dataTyper, ok := fieldValue.Interface().(GormDataTypeInterface); ok {
@@ -61,6 +64,7 @@ func (m Migrator) DataTypeOf(field *schema.Field) string {
 	return m.Dialector.DataTypeOf(field)
 }
 
+// FullDataTypeOf returns field's db full data type
 func (m Migrator) FullDataTypeOf(field *schema.Field) (expr clause.Expr) {
 	expr.SQL = m.DataTypeOf(field)
 
@@ -85,7 +89,7 @@ func (m Migrator) FullDataTypeOf(field *schema.Field) (expr clause.Expr) {
 	return
 }
 
-// AutoMigrate
+// AutoMigrate auto migrate values
 func (m Migrator) AutoMigrate(values ...interface{}) error {
 	for _, value := range m.ReorderModels(values, true) {
 		tx := m.DB.Session(&gorm.Session{})
@@ -156,12 +160,14 @@ func (m Migrator) AutoMigrate(values ...interface{}) error {
 	return nil
 }
 
+// GetTables returns tables
 func (m Migrator) GetTables() (tableList []string, err error) {
 	err = m.DB.Raw("SELECT TABLE_NAME FROM information_schema.tables where TABLE_SCHEMA=?", m.CurrentDatabase()).
 		Scan(&tableList).Error
 	return
 }
 
+// CreateTable create table in database for values
 func (m Migrator) CreateTable(values ...interface{}) error {
 	for _, value := range m.ReorderModels(values, false) {
 		tx := m.DB.Session(&gorm.Session{})
@@ -252,6 +258,7 @@ func (m Migrator) CreateTable(values ...interface{}) error {
 	return nil
 }
 
+// DropTable drop table for values
 func (m Migrator) DropTable(values ...interface{}) error {
 	values = m.ReorderModels(values, false)
 	for i := len(values) - 1; i >= 0; i-- {
@@ -265,6 +272,7 @@ func (m Migrator) DropTable(values ...interface{}) error {
 	return nil
 }
 
+// HasTable returns table exists or not for value, value could be a struct or string
 func (m Migrator) HasTable(value interface{}) bool {
 	var count int64
 
@@ -276,6 +284,7 @@ func (m Migrator) HasTable(value interface{}) bool {
 	return count > 0
 }
 
+// RenameTable rename table from oldName to newName
 func (m Migrator) RenameTable(oldName, newName interface{}) error {
 	var oldTable, newTable interface{}
 	if v, ok := oldName.(string); ok {
@@ -303,12 +312,13 @@ func (m Migrator) RenameTable(oldName, newName interface{}) error {
 	return m.DB.Exec("ALTER TABLE ? RENAME TO ?", oldTable, newTable).Error
 }
 
-func (m Migrator) AddColumn(value interface{}, field string) error {
+// AddColumn create `name` column for value
+func (m Migrator) AddColumn(value interface{}, name string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		// avoid using the same name field
-		f := stmt.Schema.LookUpField(field)
+		f := stmt.Schema.LookUpField(name)
 		if f == nil {
-			return fmt.Errorf("failed to look up field with name: %s", field)
+			return fmt.Errorf("failed to look up field with name: %s", name)
 		}
 
 		if !f.IgnoreMigration {
@@ -322,6 +332,7 @@ func (m Migrator) AddColumn(value interface{}, field string) error {
 	})
 }
 
+// DropColumn drop value's `name` column
 func (m Migrator) DropColumn(value interface{}, name string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		if field := stmt.Schema.LookUpField(name); field != nil {
@@ -334,6 +345,7 @@ func (m Migrator) DropColumn(value interface{}, name string) error {
 	})
 }
 
+// AlterColumn alter value's `field` column' type based on schema definition
 func (m Migrator) AlterColumn(value interface{}, field string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		if field := stmt.Schema.LookUpField(field); field != nil {
@@ -348,6 +360,7 @@ func (m Migrator) AlterColumn(value interface{}, field string) error {
 	})
 }
 
+// HasColumn check has column `field` for value or not
 func (m Migrator) HasColumn(value interface{}, field string) bool {
 	var count int64
 	m.RunWithValue(value, func(stmt *gorm.Statement) error {
@@ -366,6 +379,7 @@ func (m Migrator) HasColumn(value interface{}, field string) bool {
 	return count > 0
 }
 
+// RenameColumn rename value's field name from oldName to newName
 func (m Migrator) RenameColumn(value interface{}, oldName, newName string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		if field := stmt.Schema.LookUpField(oldName); field != nil {
@@ -383,6 +397,7 @@ func (m Migrator) RenameColumn(value interface{}, oldName, newName string) error
 	})
 }
 
+// MigrateColumn migrate column
 func (m Migrator) MigrateColumn(value interface{}, field *schema.Field, columnType gorm.ColumnType) error {
 	// found, smart migrate
 	fullDataType := strings.ToLower(m.DB.Migrator().FullDataTypeOf(field).SQL)
@@ -448,7 +463,7 @@ func (m Migrator) ColumnTypes(value interface{}) ([]gorm.ColumnType, error) {
 		}
 
 		for _, c := range rawColumnTypes {
-			columnTypes = append(columnTypes, c)
+			columnTypes = append(columnTypes, ColumnType{SQLColumnType: c})
 		}
 
 		return
@@ -457,10 +472,12 @@ func (m Migrator) ColumnTypes(value interface{}) ([]gorm.ColumnType, error) {
 	return columnTypes, execErr
 }
 
+// CreateView create view
 func (m Migrator) CreateView(name string, option gorm.ViewOption) error {
 	return gorm.ErrNotImplemented
 }
 
+// DropView drop view
 func (m Migrator) DropView(name string) error {
 	return gorm.ErrNotImplemented
 }
@@ -487,6 +504,7 @@ func buildConstraint(constraint *schema.Constraint) (sql string, results []inter
 	return
 }
 
+// GuessConstraintAndTable guess statement's constraint and it's table based on name
 func (m Migrator) GuessConstraintAndTable(stmt *gorm.Statement, name string) (_ *schema.Constraint, _ *schema.Check, table string) {
 	if stmt.Schema == nil {
 		return nil, nil, stmt.Table
@@ -531,6 +549,7 @@ func (m Migrator) GuessConstraintAndTable(stmt *gorm.Statement, name string) (_
 	return nil, nil, stmt.Schema.Table
 }
 
+// CreateConstraint create constraint
 func (m Migrator) CreateConstraint(value interface{}, name string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		constraint, chk, table := m.GuessConstraintAndTable(stmt, name)
@@ -554,6 +573,7 @@ func (m Migrator) CreateConstraint(value interface{}, name string) error {
 	})
 }
 
+// DropConstraint drop constraint
 func (m Migrator) DropConstraint(value interface{}, name string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		constraint, chk, table := m.GuessConstraintAndTable(stmt, name)
@@ -566,6 +586,7 @@ func (m Migrator) DropConstraint(value interface{}, name string) error {
 	})
 }
 
+// HasConstraint check has constraint or not
 func (m Migrator) HasConstraint(value interface{}, name string) bool {
 	var count int64
 	m.RunWithValue(value, func(stmt *gorm.Statement) error {
@@ -586,6 +607,7 @@ func (m Migrator) HasConstraint(value interface{}, name string) bool {
 	return count > 0
 }
 
+// BuildIndexOptions build index options
 func (m Migrator) BuildIndexOptions(opts []schema.IndexOption, stmt *gorm.Statement) (results []interface{}) {
 	for _, opt := range opts {
 		str := stmt.Quote(opt.DBName)
@@ -607,10 +629,12 @@ func (m Migrator) BuildIndexOptions(opts []schema.IndexOption, stmt *gorm.Statem
 	return
 }
 
+// BuildIndexOptionsInterface build index options interface
 type BuildIndexOptionsInterface interface {
 	BuildIndexOptions([]schema.IndexOption, *gorm.Statement) []interface{}
 }
 
+// CreateIndex create index `name`
 func (m Migrator) CreateIndex(value interface{}, name string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		if idx := stmt.Schema.LookIndex(name); idx != nil {
@@ -642,6 +666,7 @@ func (m Migrator) CreateIndex(value interface{}, name string) error {
 	})
 }
 
+// DropIndex drop index `name`
 func (m Migrator) DropIndex(value interface{}, name string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		if idx := stmt.Schema.LookIndex(name); idx != nil {
@@ -652,6 +677,7 @@ func (m Migrator) DropIndex(value interface{}, name string) error {
 	})
 }
 
+// HasIndex check has index `name` or not
 func (m Migrator) HasIndex(value interface{}, name string) bool {
 	var count int64
 	m.RunWithValue(value, func(stmt *gorm.Statement) error {
@@ -669,6 +695,7 @@ func (m Migrator) HasIndex(value interface{}, name string) bool {
 	return count > 0
 }
 
+// RenameIndex rename index from oldName to newName
 func (m Migrator) RenameIndex(value interface{}, oldName, newName string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		return m.DB.Exec(
@@ -678,6 +705,7 @@ func (m Migrator) RenameIndex(value interface{}, oldName, newName string) error
 	})
 }
 
+// CurrentDatabase returns current database name
 func (m Migrator) CurrentDatabase() (name string) {
 	m.DB.Raw("SELECT DATABASE()").Row().Scan(&name)
 	return
@@ -781,6 +809,7 @@ func (m Migrator) ReorderModels(values []interface{}, autoAdd bool) (results []i
 	return
 }
 
+// CurrentTable returns current statement's table expression
 func (m Migrator) CurrentTable(stmt *gorm.Statement) interface{} {
 	if stmt.TableExpr != nil {
 		return *stmt.TableExpr

tests/go.mod

@@ -3,17 +3,16 @@ module gorm.io/gorm/tests
 go 1.14
 
 require (
-	github.com/denisenkom/go-mssqldb v0.12.0 // indirect
 	github.com/google/uuid v1.3.0
 	github.com/jackc/pgx/v4 v4.15.0 // indirect
 	github.com/jinzhu/now v1.1.4
 	github.com/lib/pq v1.10.4
 	github.com/mattn/go-sqlite3 v1.14.11 // indirect
 	golang.org/x/crypto v0.0.0-20220214200702-86341886e292 // indirect
-	gorm.io/driver/mysql v1.2.3
+	gorm.io/driver/mysql v1.3.0
-	gorm.io/driver/postgres v1.2.3
+	gorm.io/driver/postgres v1.3.0
-	gorm.io/driver/sqlite v1.2.6
+	gorm.io/driver/sqlite v1.3.0
-	gorm.io/driver/sqlserver v1.2.1
+	gorm.io/driver/sqlserver v1.3.0
 	gorm.io/gorm v1.22.5
 )
 

tests/migrate_test.go

@@ -92,7 +92,7 @@ func TestAutoMigrateSelfReferential(t *testing.T) {
 }
 
 func TestSmartMigrateColumn(t *testing.T) {
-	fullSupported := map[string]bool{"mysql": true}[DB.Dialector.Name()]
+	fullSupported := map[string]bool{"mysql": true, "postgres": true}[DB.Dialector.Name()]
 
 	type UserMigrateColumn struct {
 		ID       uint
@@ -313,9 +313,15 @@ func TestMigrateIndexes(t *testing.T) {
 }
 
 func TestMigrateColumns(t *testing.T) {
+	fullSupported := map[string]bool{"sqlite": true, "mysql": true, "postgres": true, "sqlserver": true}[DB.Dialector.Name()]
+	sqlite := DB.Dialector.Name() == "sqlite"
+	sqlserver := DB.Dialector.Name() == "sqlserver"
+
 	type ColumnStruct struct {
 		gorm.Model
 		Name string
+		Age  int    `gorm:"default:18;comment:my age"`
+		Code string `gorm:"unique"`
 	}
 
 	DB.Migrator().DropTable(&ColumnStruct{})
@@ -340,10 +346,29 @@ func TestMigrateColumns(t *testing.T) {
 		stmt.Parse(&ColumnStruct2{})
 
 		for _, columnType := range columnTypes {
-			if columnType.Name() == "name" {
+			switch columnType.Name() {
+			case "id":
+				if v, ok := columnType.PrimaryKey(); (fullSupported || ok) && !v {
+					t.Fatalf("column id primary key should be correct, name: %v, column: %#v", columnType.Name(), columnType)
+				}
+			case "name":
 				dataType := DB.Dialector.DataTypeOf(stmt.Schema.LookUpField(columnType.Name()))
 				if !strings.Contains(strings.ToUpper(dataType), strings.ToUpper(columnType.DatabaseTypeName())) {
-					t.Errorf("column type should be correct, name: %v, length: %v, expects: %v", columnType.Name(), columnType.DatabaseTypeName(), dataType)
+					t.Fatalf("column name type should be correct, name: %v, length: %v, expects: %v, column: %#v", columnType.Name(), columnType.DatabaseTypeName(), dataType, columnType)
+				}
+				if length, ok := columnType.Length(); ((fullSupported && !sqlite) || ok) && length != 100 {
+					t.Fatalf("column name length should be correct, name: %v, length: %v, expects: %v, column: %#v", columnType.Name(), length, 100, columnType)
+				}
+			case "age":
+				if v, ok := columnType.DefaultValue(); (fullSupported || ok) && v != "18" {
+					t.Fatalf("column age default value should be correct, name: %v, column: %#v", columnType.Name(), columnType)
+				}
+				if v, ok := columnType.Comment(); ((fullSupported && !sqlite && !sqlserver) || ok) && v != "my age" {
+					t.Fatalf("column age comment should be correct, name: %v, column: %#v", columnType.Name(), columnType)
+				}
+			case "code":
+				if v, ok := columnType.Unique(); (fullSupported || ok) && !v {
+					t.Fatalf("column code unique should be correct, name: %v, column: %#v", columnType.Name(), columnType)
 				}
 			}
 		}