[SQL]insert、update 表触发器应用的demo

--创建测试表
create table student
(
    stu_id int
    ,libraryCardNo varchar()
)

create table borrowbook
(
    b_id int
    ,libraryCardNo varchar()
)

GO

--插入测试数据
insert student
select ,''
insert borrowbook
select ,''

GO

--查询数据
SELECT * FROM  student
SELECT * FROM borrowbook 

--创建触发器<更新表>
create  trigger stu_trg
on student
for update
as
    declare @a varchar()
           ,@b varchar()

           select @a=libraryCardNo ,@b=stu_id from inserted
           update borrowbook set libraryCardNo=@a where b_id=@b

GO
--创建触发器<插入表>
create trigger insert_trg
on student
for insert
as
    declare @a varchar()
           ,@b varchar()
           select @a=libraryCardNo ,@b=stu_id from inserted
           insert into borrowbook(b_id,libraryCardNo)values(@b,@a)

GO

--*********测试结果-----------------更改数据
update student set libraryCardNo='' where stu_id=
insert into student(stu_id,libraryCardNo)values(,'')
--结果对比
select * from student
select * from borrowbook