[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