触发器

create trigger tri_update
on UserCardInfo
for update
as
begin
  declare @ALLMoney int
  declare @OutMoney int
  select @ALLMoney = CardMoney from UserCardInfo
 
    declare @No varchar(50)
    declare @Name varchar(50)
    declare @Money varchar(50)
 
  begin try
  begin transaction
 
  if @OutMoney<=@ALLMoney
    begin
        update UserCardInfo set CardMoney = CardMoney - @OutMoney
        
        select @No=CardNo,@Name=Name ,@Money = CardMoney from inserted
        
        insert  into CardOperation values (@No,@Name,@Money,'取款')
    end
    commit transaction

  end try
  begin catch
  rollback transaction
  end catch
 
end