func (b *Backend) AlterField(db *sql.DB, m driver.Model, table *sql.Table, oldField *sql.Field, newField *sql.Field) error { fsql, cons, err := newField.SQL(db, m, table) if err != nil { return err } tableName := db.QuoteIdentifier(m.Table()) if _, err = db.Exec(fmt.Sprintf("ALTER TABLE %s CHANGE COLUMN %s %s", tableName, db.QuoteIdentifier(oldField.Name), fsql)); err != nil { return err } for _, c := range cons { if _, err = db.Exec(fmt.Sprintf("ALTER TABLE %s ADD CONSTRAINT %s", tableName, c)); err != nil { return err } } return err }