oracle 中两张表同步的触发器

/*创建表A*/
create table A_ybl (

   y                   INTEGER                         not null,

   b            VARCHAR(30)                     not null,

   l            VARCHAR(20)                     not null
  

);
/*创建表A的备份表*/

create table A_ybl2 (

   y                   INTEGER                         not null,

   b            VARCHAR(30)                     not null,

   l            VARCHAR(20)                     not null
  

);
create or replace trigger test
after insert or update or delete on  A_ybl for each row

declare
error_exception exception,
errno integer,
errmsg  char(20),
dummy integer,
found boolean;

begin
if inserting  then
    insert into  A_ybl2 values(:NEW.y,:NEW.B,:NEW.l);
 elsif updating then
        update A_ybl2 set y=:NEW.y,
                   b=:NEW.b,
                   l=:NEW.l
               where id:=:OLD.y;
      elsif deleting  then
          delete from A_ybl2  where y=:old.id;
 end if;
 
 exception
 
 when error_exception   then
 raise_application_error(errno,errmsg);
 end;