原文链接：http://www.cnblogs.com/maxblog/archive/2010/05/21/1741220.html
/*用触发器来实现级联更新级联删除*/
--创建学生表，课程表，学生课程表
--http://www.yaosansi.com/post/692.html
范本：
触发器方式：
create trigger trg_A
on A
for update,delete
as
begin
if exists(select 1 from inserted)
update B set Name=(select Name from inserted) where Name=(select Name from deleted)
else
delete B where Name=(select Name from deleted)
end
go
下面是一个实例：
CREATE TABLE [dbo].[学生表](
[studentid] [nvarchar](50) primary key NOT NULL,
[name] [nvarchar](50) COLLATE Chinese_PRC_CI_AS NULL,
)
CREATE TABLE [dbo].[课程表](
[courseid] [nvarchar](50) primary key NOT NULL,
[name] [nvarchar](50) COLLATE Chinese_PRC_CI_AS NULL,
)
CREATE TABLE [dbo].[学生课程表](
[studentid] [nvarchar](50) NOT NULL ,
[courseid] [nvarchar](50) NOT NULL ,
[grade] [nvarchar](50) NULL,
primary key(studentid,courseid),
)
--删除表：
drop table 学生表;
drop table 课程表;
drop table 学生课程表;
insert into 学生表values('001','张三');
insert into 学生表values('002','李四');
insert into 课程表values('101','语文');
insert into 课程表values('102','数学');
insert into 学生课程表values('001','101','63');
insert into 学生课程表values('001','102','50');
insert into 学生课程表values('002','101','73');
insert into 学生课程表values('002','102','70');
--创建一个触发器来实现级联更新级联删除
create trigger trg_A
on 学生表
for update,delete
as
begin
if exists(select 1 from inserted)
update 学生课程表set studentid=(select studentid from inserted) where studentid=(select studentid from deleted)
else
delete 学生课程表where studentid=(select studentid from deleted)
end
go
--删除操作：
delete from 学生表where studentid='001'
--更新操作
update 学生表set studentid='0001' where studentid='001'
--查询：
select * from 学生表order by studentid ;
select * from 课程表order by courseid ;
select * from 学生课程表order by studentid, courseid;