oracle中触发器将改变数据插入新表

create or replace trigger xxx1
after update on table2
for each row
begin
  if(:old.xxx_date||'A'!=:new.xxx_date||'A') then
     insert into  table3(xxxx_id,xxxx_code,xxxx_time,xxxx_name,creator)
     values(xxxx_id_sequence.nextval,"xxxx",:new.xxx_date,:new.xxx_stopname,:new.creator);
  end if;
  if(:old.yyyy_date||'A'!=:new.yyyy_date||'A') then
     insert into  table3(xxxx_id,xxxx_code,xxxx_time,xxxx_name,creator)
     values(xxxx_id_sequence.nextval,"xxxx",:new.xxx_date,:new.xxx_stopname,:new.creator);
  end if;
  if(:old.zzzz||'A'!=:new.zzzz||'A') then
      insert into  table3(xxxx_id,xxxx_code,xxxx_time,xxxx_name,creator)
     values(xxxx_id_sequence.nextval,"xxxx",:new.xxx_date,:new.xxx_stopname,:new.creator);
  end if;
end xxx1;