Question

你好，我做一个SQL SERVER的级联删除的触发器

我有三张表ABC 这样的主外键关系,A.ID=B.ID A.ID=C.ID
我想做一个删除A表某字段，删除时触发一个触发器，同时删除B、C ID主外键关系的字段。
问题一：触发器语句，不要复制的。谢谢

Answer 1

create trigger delete_B_C
on A
for delete
as
begin
delete from B B1 join deleted D1
on B1.Id=D1.Id

delete from C C1 join deleted D1
on C1.Id=D1.Id
end

追问

deleted 是什么意思？

delete from Grade B1 join student D1 on B1.studentid=D1.studentid
delete from class C1 join student D1
on C1.studentid=D1.studentid

student表=A
Grade表 =B
class表 =C

追答

在SQL中存在两个隐藏表，该表在执行过程中存在的，执行完毕后是不存在的！这两个表就是deleted和inserted表，当进行删除时，先将删除数据存入到deleted表中，然后在任务提交后清空deleted表（表在任务提交后就已经不存在了），而进行插入时，插入数据也是先存储在inserted表中，任务得提交后，该表也不会存在了！

追问

追答

改成：
delete from B
where id in
(
select id from deleted
)

delete from C
where id in
(
select id from deleted
)