--创建交易详细表 use MoneyManager if(exists(select * from sysobjects where name='transinfo'))    drop table transinfo create table transinfo (    id varchar(20) primary key not null,    transdate date,    tarnstype nvarchar(2),    transmoney money,    remark nvarchar(256) ) go --给表transinfo创建插入触发器，给交易表插入一条交易信息，更新账户余额。 alter trigger tg_transifno_insert on transinfo after insert --for等价于after是已经插入基表，可以回滚回去。instead of 还没有插入基表 as declare @userid varchar(20) declare @money money declare @type nvarchar(2) declare @yue money set nocount on select @userid=id,@money=transmoney,@type=tarnstype from inserted if(@type='支取') begin               select  @yue=[money] from t_money where userid=@userid       print('支取前的余额是:'+convert(varchar(10),@yue))       update t_money set [money]=[money]-@money where userid=@userid       print('支取了：'+convert(varchar(10),@money))       select  @yue=[money] from t_money where userid=@userid       print('支取后的余额是:'+convert(varchar(10),@yue)) end else if(@type='存入') begin               select  @yue=[money] from t_money where userid=@userid        print('存入前的余额是:'+convert(varchar(10),@yue))        update t_money set [money]=[money]+@money where userid=@userid        print('存入了:'+convert(varchar(10),@money))        select  @yue=[money] from t_money where userid=@userid        print('存入后的余额是:'+convert(varchar(10),@yue)) end go --测试语句 insert into transinfo values (2222,GETDATE(),'支取',300,''); go --给表transinfo创建删除触发器，删除一条交易信息，并备份到transbacktable表 alter trigger tg_transinfo_delete on transinfo for delete as    set nocount no    if(not Exists(select * from sysobjects where name='transbacktable'))    begin     select * into transbacktable from deleted     end     else     begin        insert into transbacktable select * from deleted     end  go --测试语句    delete from dbo.transinfo where id='2222' go  --给表t_money创建更新发器，单笔交易大于500就停止交易  create trigger tg_t_money_update  on t_money  for update  as    set nocount no    declare @beformoney money    declare @aftermoney money    select @beformoney=[money] from deleted    select @aftermoney=[money] from inserted    if(abs(@aftermoney-@beformoney)>500)    begin        raiserror('单笔交易不能大于500',16,1)        rollback transaction    end go --测试语句 update t_money set [money]=[money]+500 go  --给表transinfo的transdate列创建更新发器，禁止更新  create trigger tg_transinfo_transdateupdate  on transinfo  for update  as  set nocount on  if(update(transdate))  begin      raiserror('禁止更改交易时间',16,1)      rollback transaction  end  go