触发器是自动的：它们在对表的数据作了任何修改（比如手工输入或者应用程序采取的操作）之后立即被激活。
if exists(select * from sysobjects where name = 'Tbl_periodPara_Update_Trigger' )
drop TRIGGER Tbl_periodPara_Update_Trigger
GO
create TRIGGER Tbl_periodPara_Update_Trigger
on tbl_periodPara
for update
as RAISERROR ('Job id 1 expects the default level of 10.', 16, 1)
GO www.2cto.com
update tbl_periodPara set iPeriod = 4 where strName = 'SysSamplePara'
sp_helptrigger 'tbl_periodPara','update'
select * from sysobjects where name = 'Tbl_periodPara_Update_Trigger'