求一最基础的触发器语句!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[v41dugu]

有两个表 books和newbook
当删除books中的某行时 ,如果在newbook中也有这本书 同时也要删除 (两个表中都有个bookid的列 存放书的id)
我想用触发器实现 应该怎么写?

[Limpire]

create trigger tr_books
on books
for delete
as
set nocount on
delete a from newbook a, deleted b where a.bookid = b.bookid
set nocount off
go

[v41dugu]

请问这个set nocount on 和set nocount off是什么意思?

[Limpire]

select top 1 * from sysobjects

消息里显示：（所影响的行数为 1 行）

set nocount on：不显示这个消息
set nocount off：显示

[v41dugu]

create trigger tg_DeleteOnBooks on books for delete
as
delete from newbook,deleted where newbook.bookid=deleted.bookid

这样为什么错了啊?

[chuifengde]

你上面delete 删除，删的是什么表呢，所以错，可以
delete newbook from deleted where newbook.bookid=deleted.bookid

[Limpire]

create trigger tg_DeleteOnBooks on books for delete
as
delete from newbook,deleted where newbook.bookid=deleted.bookid

这样为什么错了啊?
-----------------------------
我写的没错啊，你没理解透：
delete a from newbook a, deleted b where a.bookid = b.bookid

[v41dugu]

恩 我懂了 谢谢了哈 各位

[衣犹未尽]

请问这个set nocount on 和set nocount off是什么意思?
---------------------------------

当 SET NOCOUNT 为 ON 时，将不给客户端发送存储过程中的每个语句的 DONE_IN_PROC 信息
如果存储过程中包含的一些语句并不返回许多实际的数据，则该设置由于大量减少了网络流量，因此可显著提高性能。

为off的时候作用就相反了