SQL触发器

create trigger [shema_name . ] trg_nameon { table | view }[ with encryption ]{ for | after | instead of }{ insert , update , delete }assql_statement

insert触发器实例

create trigger teston alfor insertasdeclare @id int,@uid int,@lid int,@result charselect @id=id,@uid=uid,@lid=lid,@result=result from insertedif(@lid=4)begin   update al set uid=99 where id=@id   PRint 'lid=4时自动修改用户id为99'end

update触发器实例

create trigger test_updateon al   for updateas   declare @oldid int,@olduid int,@oldlid int,@newid int,@newuid int,@newlid int   select @oldid=id,@olduid=uid,@oldlid=lid from deleted;   select @newid=id,@newuid=uid,@newlid=lid from inserted   if(@newlid>@oldlid)   begin   print 'newlid>oldid'   rollback tran;   end   else   print '修改成功'

delete触发器实例

create trigger test_delete on al for delete as declare @did int,@duid int,@dlid int select @did=id,@duid=uid,@dlid=lid from deleted if(exists(select * from list where @dlid=id)) begin print '无法删除' rollback tran; end else print '删除成功'