return "CONSTRAINT ? CHECK (?)", []interface{}{clause.Column{Name: chk.Name}, clause.Expr{SQL: chk.Constraint}}
}

// ParseCheckConstraints parse schema check constraints
func (schema *Schema) ParseCheckConstraints() map[string]CheckConstraint {
	checks := map[string]CheckConstraint{}
	for _, field := range schema.FieldsByDBName {
		if chk := field.TagSettings["CHECK"]; chk != "" {
			names := strings.Split(chk, ",")

		// wait for other goroutines prepared
		<-stmt.prepared
		if stmt.prepareErr != nil {
			return Stmt{}, stmt.prepareErr
		}

		return *stmt, nil
	}
	db.Mux.RUnlock()

	db.Mux.Lock()
	// double check
	if stmt, ok := db.Stmts[query]; ok && (!stmt.Transaction || isTransaction) {
		db.Mux.Unlock()
		// wait for other goroutines prepared
		<-stmt.prepared
		if stmt.prepareErr != nil {
			return Stmt{}, stmt.prepareErr

	ErrForeignKeyViolated = errors.New("violates foreign key constraint")
	// ErrCheckConstraintViolated occurs when there is a check constraint violation
	ErrCheckConstraintViolated = errors.New("violates check constraint")

}

// ViewOption view option
type ViewOption struct {
	Replace     bool   // If true, exec `CREATE`. If false, exec `CREATE OR REPLACE`
	CheckOption string // optional. e.g. `WITH [ CASCADED | LOCAL ] CHECK OPTION`
	Query       *DB    // required subquery.
}

// ColumnType column type interface
type ColumnType interface {
	Name() string
	DatabaseTypeName() string                 // varchar

			t.Fatalf("Should have index on %s", "CompanyI.")
		}

		if !m.HasIndex(&DynamicUser{}, "DeletedAt") {
			t.Fatalf("Should have index on deleted_at.")
		}
	}
}

// check column order after migration, flaky test
// https://github.com/go-gorm/gorm/issues/4351
func TestMigrateColumnOrder(t *testing.T) {
	type UserMigrateColumn struct {
		ID uint
	}

	var (
		alterColumn bool
		isSameType  = fullDataType == realDataType
	)

	if !field.PrimaryKey {
		// check type
		if !strings.HasPrefix(fullDataType, realDataType) {
			// check type aliases
			aliases := m.DB.Migrator().GetTypeAliases(realDataType)
			for _, alias := range aliases {
				if strings.HasPrefix(fullDataType, alias) {
					isSameType = true

	}

	if len(omits) > 0 {
		tx = tx.Omit(omits...)
	}

	return db.AddError(tx.Create(values).Error)
}

// check association values has been saved
// if values kind is Struct, check it has been saved
// if values kind is Slice/Array, check all items have been saved
var visitMapStoreKey = "gorm:saved_association_map"

func checkAssociationsSaved(db *gorm.DB, values reflect.Value) bool {

		}
	}

	return ""
}

func IsValidDBNameChar(c rune) bool {
	return !unicode.IsLetter(c) && !unicode.IsNumber(c) && c != '.' && c != '*' && c != '_' && c != '$' && c != '@'
}

// CheckTruth check string true or not
func CheckTruth(vals ...string) bool {
	for _, val := range vals {
		if val != "" && !strings.EqualFold(val, "false") {
			return true
		}
	}
	return false
}

	}
}

func TestPostgres(t *testing.T) {
	if DB.Dialector.Name() != "postgres" {
		t.Skip()
	}

	type Harumph struct {
		gorm.Model
		Name      string         `gorm:"check:name_checker,name <> ''"`
		Test      uuid.UUID      `gorm:"type:uuid;not null;default:gen_random_uuid()"`
		CreatedAt time.Time      `gorm:"type:TIMESTAMP WITHOUT TIME ZONE"`

		t.Fatalf("failed to parse pointer user, got error %v", err)
	}

	checkUserSchema(t, user)
}

func checkUserSchema(t *testing.T, user *schema.Schema) {
	// check schema
	checkSchema(t, user, schema.Schema{Name: "User", Table: "users"}, []string{"ID"})

	// check fields
	fields := []schema.Field{