写了个 insert触发器不起作用

[yoopk]

create or replace trigger ChangeCalendarIdTrigger
after insert on KM_CALENDAR_MAIN
for each row
declare --这里是关键的地方，在变量申明的地方，指定自定义事务处理。
pragma autonomous_transaction;
begin
update KM_CALENDAR_MAIN
set DOC_OWNER_ID =(select FD_ID from SYS_ORG_ELEMENT where KM_CALENDAR_MAIN.DOC_CREATOR_NAME=SYS_ORG_ELEMENT.FD_NAME)
WHERE :old.DOC_OWNER_ID is null;
commit;
end;


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目的是当表A插入数据时，根据插入数据中字段的值把表B中对应字段的值更新到新插入表A的数据中。

[卖水果的net]

create or replace trigger ChangeCalendarIdTrigger
    after insert on KM_CALENDAR_MAIN
    for each row
begin
    if :old.DOC_OWNER_ID is null then
        select FD_ID
          into :new.DOC_OWNER_ID
          from SYS_ORG_ELEMENT
         where :new.DOC_CREATOR_NAME = FD_NAME;
    end if;
end;