触发器

create or replace trigger temp_trr after---用触发器实现表的同步
  insert or update or delete on testmeger for each row
  begin
   case
     when inserting then
         insert into test2meger values(:new.product_id,:new.product_name,:new.category);--插入
     when updating then
         update test2meger t2 set t2.product_name=:new.product_name,t2.category=:new.category where t2.product_id=:old.product_id;--更新
     when deleting then
         delete test2meger t2 where t2.product_id=:old.product_id;---删除
     end