触发器2.txt

很简单的小程序

 create or replace trigger jhp
 before insert on jhand
 for each row
 declare
 v_jsl base.jsl%type;
 begin
 select jsl into v_jsl from base where base.jid=:new.jid;
 if (v_jsl<:new.hsl) then
 raise_application_error(-20500,'数量不足，请等待教材入库!');
 end if;
 end;