触发器－能对表自己删除嘛问题补充

Create trigger edpshdb_eve before insert on eve
  For each row
Begin
  Set  @mount_of_eve = (Select  count(*)  from eve);
    If  (@mount_of_eve>=70)  then
        Delete from eve limit 1 ;
    End if;
End;
创建这个edpshdb_eve触发器成功，但是在我运行我的软件insert数据时失败，出现如下提示：error[can't update table' eve' in stored founction/trigger because it is already used by statement which invoked this stored founction /trigger.] failed to dump event.
希望有高人知道答案。。。。。。