触发器---特殊的存储过程，通过增减改数据来自动引发

create  trigger  TR_student_insert  (TR_表明_操作)

on student

for insert（for 是新增之后触发）

as

begin

end

go

----------------------------------------------------------

alter  trigger TR_student_insert

on student

for insert

as

begin

update student  set sname='大混蛋' where  sname='王八蛋'

end

go

insert into Student values (304,'王八蛋','男','1990-12-14','95031')

insert into Student values(306,'大混蛋','男','1992-09-02','95035')

 select *from Student

 

alter trigger TR_student_delete

 on student

 instead of delete

 as

  begin

    declare @sno int

    select @sno=sno from deleted

    delete from score where

    delete from student where

  end

 go

 delete from Student where Sno=304

 select *from Student  insert into Score  values(304,'3-105',98)

 select *from Score

 

 

 create trigger TR_student_inserted

 on student

 instead of insert

 as

 begin

 declare @sno int,@sname varchar(20),@ssex varchar(20),@sbirthday datetime,@class varchar(20)

 select @sno=sno,@sname=sname,@ssex=ssex,@sbirthday=sbirthday,@class=class from inserted

   if @ssex='男'

   begin

     set @ssex='1'

   end

 

 insert into student values (@sno,@sname,@ssex,@sbirthday,@class)

 end

 go

  insert into Student values(303,'李白','男','1992-03-12','95033')

 select  *from Student

 

 inserted---临时表 ，获取数据 ，此题中  inserted  代替触发器外的insert。

 ---触发器中的insert是把执行后的inserted 插入到student表中