create trigger calc_code_t_update_row
  after UPDATE
  on calc_code
  for each row
  BEGIN
    IF NEW.code != OLD.code
    THEN INSERT INTO calc_code_backup
    (calc_id, user_id, code, local_code, calc_width, status)
    VALUES
      (OLD.calc_id, OLD.user_id, OLD.code, OLD.local_code, OLD.calc_width, OLD.status);
    END IF;
  END;