}
	}

	db.RowsAffected = 0

	switch dest := db.Statement.Dest.(type) {
	case map[string]interface{}, *map[string]interface{}:
		if initialized || rows.Next() {
			columnTypes, _ := rows.ColumnTypes()
			prepareValues(values, db, columnTypes, columns)

			db.RowsAffected++
			db.AddError(rows.Scan(values...))

			mapValue, ok := dest.(map[string]interface{})
			if !ok {

			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)
	execErr := m.RunWithValue(value, func(stmt *gorm.Statement) (err error) {

pkg database/sql, method (*ColumnType) DatabaseTypeName() string
pkg database/sql, method (*ColumnType) DecimalSize() (int64, int64, bool)
pkg database/sql, method (*ColumnType) Length() (int64, bool)
pkg database/sql, method (*ColumnType) Name() string
pkg database/sql, method (*ColumnType) Nullable() (bool, bool)
pkg database/sql, method (*ColumnType) ScanType() reflect.Type

	NewValuePool           FieldNewValuePool

	// In some db (e.g. MySQL), Unique and UniqueIndex are indistinguishable.
	// When a column has a (not Mul) UniqueIndex, Migrator always reports its gorm.ColumnType is Unique.
	// It causes field unnecessarily migration.
	// Therefore, we need to record the UniqueIndex on this column (exclude Mul UniqueIndex) for MigrateColumnUnique.
	UniqueIndex string
}