feat: add MigrateColumnUnique (go-gorm#6640)

* feat: add MigrateColumnUnique

* feat: define new methods

* delete debug in test

Author: black-06

migrator.go

@@ -87,6 +87,8 @@ type Migrator interface {
 	DropColumn(dst interface{}, field string) error
 	AlterColumn(dst interface{}, field string) error
 	MigrateColumn(dst interface{}, field *schema.Field, columnType ColumnType) error
+	// MigrateColumnUnique migrate column's UNIQUE constraint, it's part of MigrateColumn.
+	MigrateColumnUnique(dst interface{}, field *schema.Field, columnType ColumnType) error
 	HasColumn(dst interface{}, field string) bool
 	RenameColumn(dst interface{}, oldName, field string) error
 	ColumnTypes(dst interface{}) ([]ColumnType, error)

migrator/migrator.go

@@ -27,6 +27,8 @@ var regFullDataType = regexp.MustCompile(`\D*(\d+)\D?`)
 
 // TODO:? Create const vars for raw sql queries ?
 
+var _ gorm.Migrator = (*Migrator)(nil)
+
 // Migrator m struct
 type Migrator struct {
 	Config
@@ -539,6 +541,26 @@ func (m Migrator) MigrateColumn(value interface{}, field *schema.Field, columnTy
 	return nil
 }
 
+func (m Migrator) MigrateColumnUnique(value interface{}, field *schema.Field, columnType gorm.ColumnType) error {
+	unique, ok := columnType.Unique()
+	if !ok || field.PrimaryKey {
+		return nil // skip primary key
+	}
+	// By default, ColumnType's Unique is not affected by UniqueIndex, so we don't care about UniqueIndex.
+	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
+		// We're currently only receiving boolean values on `Unique` tag,
+		// so the UniqueConstraint name is fixed
+		constraint := m.DB.NamingStrategy.UniqueName(stmt.Table, field.DBName)
+		if unique && !field.Unique {
+			return m.DB.Migrator().DropConstraint(value, constraint)
+		}
+		if !unique && field.Unique {
+			return m.DB.Migrator().CreateConstraint(value, constraint)
+		}
+		return nil
+	})
+}
+
 // ColumnTypes return columnTypes []gorm.ColumnType and execErr error
 func (m Migrator) ColumnTypes(value interface{}) ([]gorm.ColumnType, error) {
 	columnTypes := make([]gorm.ColumnType, 0)

schema/naming.go

@@ -19,13 +19,16 @@ type Namer interface {
 	RelationshipFKName(Relationship) string
 	CheckerName(table, column string) string
 	IndexName(table, column string) string
+	UniqueName(table, column string) string
 }
 
 // Replacer replacer interface like strings.Replacer
 type Replacer interface {
 	Replace(name string) string
 }
 
+var _ Namer = (*NamingStrategy)(nil)
+
 // NamingStrategy tables, columns naming strategy
 type NamingStrategy struct {
 	TablePrefix         string
@@ -85,6 +88,11 @@ func (ns NamingStrategy) IndexName(table, column string) string {
 	return ns.formatName("idx", table, ns.toDBName(column))
 }
 
+// UniqueName generate unique constraint name
+func (ns NamingStrategy) UniqueName(table, column string) string {
+	return ns.formatName("uni", table, ns.toDBName(column))
+}
+
 func (ns NamingStrategy) formatName(prefix, table, name string) string {
 	formattedName := strings.ReplaceAll(strings.Join([]string{
 		prefix, table, name,

tests/associations_belongs_to_test.go

@@ -278,8 +278,6 @@ func TestBelongsToAssociationUnscoped(t *testing.T) {
 		t.Fatalf("failed to create items, got error: %v", err)
 	}
 
-	tx = tx.Debug()
-
 	// test replace
 	if err := tx.Model(&item).Association("ItemParent").Unscoped().Replace(&ItemParent{
 		Logo: "updated logo",

tests/count_test.go

@@ -29,7 +29,7 @@ func TestCountWithGroup(t *testing.T) {
 	}
 
 	var count2 int64
-	if err := DB.Debug().Model(&Company{}).Where("name in ?", []string{"company_count_group_b", "company_count_group_c"}).Group("name").Count(&count2).Error; err != nil {
+	if err := DB.Model(&Company{}).Where("name in ?", []string{"company_count_group_b", "company_count_group_c"}).Group("name").Count(&count2).Error; err != nil {
 		t.Errorf(fmt.Sprintf("Count should work, but got err %v", err))
 	}
 	if count2 != 2 {

tests/preload_test.go

@@ -429,7 +429,6 @@ func TestEmbedPreload(t *testing.T) {
 		},
 	}
 
-	DB = DB.Debug()
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			actual := Org{}

tests/update_test.go

@@ -838,7 +838,7 @@ func TestSaveWithHooks(t *testing.T) {
 	saveTokenOwner := func(owner *TokenOwner) (*TokenOwner, error) {
 		var newOwner TokenOwner
 		if err := DB.Transaction(func(tx *gorm.DB) error {
-			if err := tx.Debug().Session(&gorm.Session{FullSaveAssociations: true}).Save(owner).Error; err != nil {
+			if err := tx.Session(&gorm.Session{FullSaveAssociations: true}).Save(owner).Error; err != nil {
 				return err
 			}
 			if err := tx.Preload("Token").First(&newOwner, owner.ID).Error; err != nil {