创建现有的mysql触发器后，是否可以对其进行修改? [英] Can you modify an existing mysql trigger after it has been created?

问题描述

在mysql中，我可以创建一个触发器，然后显示有关它的信息，如下所示:

In mysql I can create a trigger, and then show information about it like this:

mysql> show triggers like 'fooTrigger';

此命令提供的输出看起来非常像select语句，并且一行显示了匹配的触发器.可以更新显示给我的行上的一列吗?

This command gives output that looks an awful lot like a select statement, with a row showing the matching trigger. Is it possible to update a column on the row it shows me?

例如，一列名为Statement，它定义了激活触发器时发生的情况.是否可以更改fooTrigger的Statement字段，以便触发器执行其他操作?还是我需要drop然后重新create触发器?

For example, one column is named Statement, and it defines what happens when the trigger is activated. Is it possible to change the Statement field for fooTrigger so the trigger does something different? Or do I need to drop and re-create the trigger?

推荐答案

从MySQL 5.5开始，您必须删除并重新创建触发器.
不删除触发器就无法更新Statement列.

As of MySQL 5.5, you must drop and re-create the trigger.
It is not possible to update the Statement column without dropping the trigger.

文档:创建触发器 您还可以使用INFORMATION_SCHEMA表访问有关触发器的信息:

You may also access information about triggers using the INFORMATION_SCHEMA tables:

SELECT * FROM INFORMATION_SCHEMA.TRIGGERS

但是，由于这些表实际上是视图，因此不能在它们上使用UPDATE.
与使用SHOW TRIGGERS相比，这是访问和处理信息的一种更方便的方法.

But, as these tables are actually views, you can't use UPDATE on them.
It's just a more convenient way to access and manipulate the information than using SHOW TRIGGERS.

文档: INFORMATION_SCHEMA.TRIGGERS

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