在SQL Server 中,触发器(Triggers)是一种特殊的存储过程,它会在特定事件发生时自动执行。当涉及到对数据的插入(INSERT)、更新(UPDATE)或删除(DELETE)操作时,我们有两种主要的触发器类型:INSTEAD OF 触发器和 AFTER 触发器。本文将帮助您理解这两者的区别,并指导您如何实现它们。 触发器概述
创建INSTEAD OF DELETE触发器 CREATETRIGGERtr_InsteadOfDeleteONvw_Products INSTEADOFDELETEASBEGIN-- 执行自定义逻辑,比如从Products表中删除数据DELETEpFROMProducts pINNERJOINdeleted dONp.ID=d.ID;END; 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 4. 测试INSTEAD OF触发器 最后,我们可以对视图进行INSERT、UP...
DDL是SQL Server 2005的新触发器,允许响应数据库引擎中对象定义水平事件(例如:DROP TABLE语句)。INSTEAD-OF触发器是对象,在数据库引擎中可以取代数据操作语句而执行。例如:将INSTEAD-OF INSERT触发器附加到表,告诉数据库执行此触发器。 使用INSTEAD-OF触发器的理由 INSTEAD-OF触发器是SQL Sever功能强大的对象,允许开发...
instead of Delete as begin select 学号, 姓名 from deleted end delete from 学生where 学号= 4上例中定义了“trigger学生_Delete”触发器,该触发器从“delete”表中打印出所要删除的学生.在执行“delete”操作后,会发现“学号 = 4”的学生并未被删除, 原因在于“trigger学生Delete”替代了所要执行的“delete...
ENSELECT [Spid] = session_Id, ecid, [Database] = DB_NAME(sp.dbid), [User] = nt_...
本次练习将通过具体的例子介绍如何使用INSTEAD OF触发器,使读者掌握INSTEAD OF触发器的使用方法。 向student表中插入数据时,检查学号是否存在于student表中,如存在则进行插入操作,否则就不插入,具体语句如下所示: CREATE TRIGGER [checkid] ON dbo.student INSTEAD OF insert AS IF NOT EXISTS(SELECT * FROM dbo....
Okay, so I thought SQL Server 2000 was going to have some extra features that 7.0 didn't have, sort of like going from 6.0 to 6.5. Well, SQL Server 2000 is to 7.0 what 7.0 was to 6.5. This release is just jammed with features, and one of them is INSTEAD OF triggers. I'll ...
Okay, so I thought SQL Server 2000 was going to have some extra features that 7.0 didn't have, sort of like going from 6.0 to 6.5. Well, SQL Server 2000 is to 7.0 what 7.0 was to 6.5. This release is just jammed with features, and one of them is INSTEAD OF triggers. I'll ...
instead of ,before,都是在操作之前触发的一系列的动作 主要是区别是一前一后，可根据实际情况来用 例子：下面就是在更新之前做的判断！如果是更新字段A,就会更新不成功，CREATE TRIGGER UP_tabel ON table before UPDATE AS if update(字段A)begin raiserror 99999 ' 不能修改! 'rollback ...
禁用启用触发器 禁用:alter table 表名 disable trigger 触发器名称 启用:alter table 表名 enable trigger 触发器名称 如果有多个触发器,则各个触发器名称之间用英文逗号隔开。 如果把“触发器名称”换成“ALL”,则表示禁用或启用该表的全部触发器。 END. 参考: cnblogs.com/wangprince2 ...