第二个删除型触发器.sql

本套光盘提供了本书各章实例的所需的部分源程序文件以及数据库文件。读者 需要使用JDK 1.4(必需）版

/*定义第二个删除型触发器*/
CREATE trigger t_products
ON products
FOR DELETE
AS

/*显示信息代表触发器执行*/
PRINT 'DELETE trigger on the products table is executing '

/*声明一个临时变量用来存储将要删除表的顺序*/
DECLARE @product_id char (4),
@mesg varchar (40)
SELECT @product_id=productid
FROM deleted
GROUP BY productid
IF @@rowcount = 0
BEGIN
PRINT 'no rows affected on the products table'
RETURN
END

/*删除产品记录*/
SELECT @mesg='deleting discounts for products' + @mesg
PRINT @mesg
DELETE discounts
WHERE productid=@product_id