mysql - 使用触发器取消删除

Question

我想取消 DELETE 触发。这个想法是在删除之前，设置列 hide = "Y" 然后取消 TRIGGER 事件，而不是真正删除该行。

可能吗？

Answer 1

您可以取消删除，但无法更改 DELETE 触发器中的值。

DELIMITER $$

CREATE TRIGGER bd_t1_each BEFORE DELETE ON t1 FOR EACH ROW
BEGIN
  //This will not work, because the `NEW` virtual table does not exist in a delete trigger.
  SET NEW.hide = 'Y';
  //Raising an error will work.
  SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'DELETE canceled'; 
END $$

DELIMITER ;

相反，您应该创建一个存储过程来隐藏您的行:

DELIMITER $$

CREATE PROCEDURE delete_t1_row (pID INTEGER)
BEGIN
  UPDATE t1 SET hide = 'Y' WHERE id = pID;
END $$

DELIMITER ;