触发器的问题

Question

有两个表：
表1 card_info （CARD_NO,xm,xb，hj） 其中card_no 是主键  （主表）
表2 card_charge_record (autoid,CARD_NO,XM,je)  autoid 是主键 (这个表是存明细的)
现在是想当表1中 card_no 号改变时即时更新表2 使其与表1同步
CREATE OR REPLACE TRIGGER card_info_update_card_no
  AFTER UPDATE of card_no
  ON card_info
  FOR EACH ROW
  when  (new.card_no<> old.card_no) 
  DECLARE
 --   ls_pm   mzfymx.pm%type:='';
  
BEGIN
 update card_charge_record set card_no = :new.card_no  where CARD_NO = :old.card_no;
END;
/
触发器编译正常但，就是不能改变表2的值

Answer 1

drop table t1;
drop table t2;
create table t1(id int,name varchar2(10));
create table t2(id int,name varchar2(10));
insert into t1 values(1,'1');
insert into t1 values(2,'2');
insert into t1 values(3,'3');
insert into t2 values(1,'1');
insert into t2 values(1,'2');
insert into t2 values(1,'3');
commit;
select * from t1;
                                     ID NAME
--------------------------------------- ----------
                                      1 1
                                      2 2
                                      3 3
                                      
select * from t2;
                                     ID NAME
--------------------------------------- ----------
                                      1 1
                                      1 2
                                      1 3
create or replace trigger tri_t1_update
  after update of id on t1
  for each row
  when (new.id <> old.id)
begin
  update t2 set t2.id = :new.id where t2.id = :old.id;
end;
/update t1 set id=4 where id=1;   --更新id=1的记录
commit;
select * from t1;
                                     ID NAME
--------------------------------------- ----------
                                      4 1
                                      2 2
                                      3 3
select * from t2;
                                     ID NAME
--------------------------------------- ----------
                                      4 1
                                      4 2
                                      4 3