3. 创建INSTEAD OF UPDATE触发器 然后,我们需要创建触发器,以便在更新操作发生时执行特定的逻辑。以下是创建触发器的 SQL 代码: CREATETRIGGERtrg_InsteadOfUpdateONEmployees INSTEADOFUPDATEASBEGIN-- 更新前,输出相关信息DECLARE@EmployeeIDINT,@EmployeeNameNVARCHAR(100),@SalaryDECIMAL(10,2);SELECT@EmployeeID=Empl...
This solution works because an INSTEAD OF UPDATE trigger does not have to process data from theinsertedcolumns that are not updated. In theinsertedtable passed to an INSTEAD OF UPDATE trigger, the columns specified in the SET clause follow the same rules as theinsertedcolumns in an INSTEAD OF ...
是SQL server 提供给程序员和数据分析员来保证数据完整性的一种方法,它是与表事件相关的特殊的存储过程,它的执行不是由程序调用,也不是手工启动,而是由事件来触发,比如当对一个表进行操作( insert,delete, update)时就会激活它执行。触发器经常用于加强数据的完整性约束和业务规则等。 触发器可以从 DBA_TRIGGERS ...
Each table or view can have one INSTEAD OF trigger for each triggering action (UPDATE, DELETE, and INSERT). 展开表 注意 If an application calls InsteadOfTrigger on an instance of Microsoft SQL Server version 7.0, the constant, SQLDMO_E_SQL80ONLY, and the message "This property or method...
Since cascading DELETEs and UPDATEs weren't provided through declarative RI until the release of SQL Server 2000, the only way to do this nicely was to use triggers, since any referential integrity constraints would restrict the DELETE or UPDATE. Sure, you could also do this in a stored ...
Since cascading DELETEs and UPDATEs weren't provided through declarative RI until the release of SQL Server 2000, the only way to do this nicely was to use triggers, since any referential integrity constraints would restrict the DELETE or UPDATE. Sure, you could also do this in a stored ...
Drop Trigger Trig_Insert_ViewTeacher Go Create Trigger Trig_Insert_ViewTeacher ON View_Teacher Instead Of Insert As Begin Set Nocount On -- 检查PeopleID是否重复,不重复则插入记录 If (Not Exists (Select P.PeopleID From People P, Inserted I ...
Inside SQL Server INSTEAD OF Triggers Keep data changes in check with this new trigger type Kalen Delaney Since its first release, SQL Server has had a mechanism to provide an automated response whenever a user or an application changes data. This mechanism is a trigger, which is a special ...
Create Trigger Trig_Insert_ViewTeacher ON View_Teacher Instead Of Insert As Begin Set Nocount On -- 检查PeopleID是否重复,不重复则插入记录 If (Not Exists (Select P.PeopleID From People P, Inserted I Where P.PeopleID = I.PeopleID)) ...
--创建一个基于UPDATE 的INSTEAD OF 触发器 CREATE OR REPLACE TRIGGER tr_vw_dept_emp INSTEAD OF UPDATE ON vw_dept_emp FOR EACH ROW BEGIN UPDATE dept SET dname=:new.dname WHERE deptno=:old.deptno; END; --更新视图 scott@ORCL> update vw_dept_emp set dname='Developement' where deptno=20; ...