oracle触发器例子

--建表：
create table zhidao_20131014_tab2_1
(
       HEAD_ID  varchar2(10),
       LINE_ID  varchar2(10),
       QTY  number
);
create table zhidao_20131014_tab2_2
(
       HEAD_ID  varchar2(10),
       SUMQTY  number
);
--造数：
insert into zhidao_20131014_tab2_1
select 'H1','1',100 from dual
union all
select 'H1','2',200 from dual
union all
select 'H1','2',300 from dual
union all
select 'H1','2',100 from dual;
 
insert into zhidao_20131014_tab2_2
select 'H1',700 from dual;
commit;
--触发器：
create or replace trigger tr_zhidao
after insert or update or delete
on zhidao_20131014_tab2_1
for each row
begin
  case
    when updating then
      update zhidao_20131014_tab2_2 t set SUMQTY=SUMQTY - :o1ld.QTY + :new.QTY where t.head_id=:new.head_id;
    when inserting then
      update zhidao_20131014_tab2_2 t set SUMQTY=SUMQTY + :new.QTY where t.head_id=:new.head_id;
    when deleting then
      update zhidao_20131014_tab2_2 t set SUMQTY=SUMQTY - :old.QTY where t.head_id=:old.head_id;
  end case;
end;
--测试：
--insert
insert into zhidao_20131014_tab2_1 
select 'H1','3',300 from dual;
--delete
delete zhidao_20131014_tab2_1 where HEAD_ID='H1' and LINE_ID='3';
--update
update zhidao_20131014_tab2_1 set QTY=1000 where QTY=300;