簡單觸發(fā)器的使用 獻給SQL初學者

IF EXISTS(SELECT * FROM sysobjects
WHERE name='tr_Users_OnUpdate' AND TYPE='TR')
DROP TRIGGER tr_Users_OnUpdate
GO --這里呢創(chuàng)建觸發(fā)器與存儲過程類似（都是DDL）
--先判斷如否存在同名觸發(fā)器就刪除然后重建
CREATE TRIGGER tr_Users_OnUpdate
ON Users FOR UPDATE
AS PRINT ‘Users表已發(fā)生修改'
GO

--添加留言的觸發(fā)器
IF EXISTS(SELECT name FROM sysobjects WHERE name='tr_LeaveWord_Add' AND TYPE='TR')
DROP TRIGGER tr_LeaveWord_Add
GO
CREATE TRIGGER tr_LeaveWord_Add
ON WordInfo FOR INSERT
AS UPDATE UserInfo SET LeaveCount=LeaveCount+1
WHERE UserID=(SELECT TOP 1 UserID FROM Inserted)
GO