Question

我有桌子

messages ( 
  id number, 
  mess varchar2(4000), 
  short_mess(100) )

我想创建类似的东西的触发器：

INSERT into messages ( id, message ) values ( some_id, some_message)

然后在表格messages中，我希望( some_id, some_message, some_message_shortcut)

我的触发器如下所示：

create or replace trigger "MESSAGES_T1"
AFTER
insert on "MESSAGES"
for each row
begin
UPDATE  MESSAGES set "short_mess" = 'aaa'
where id = :new.id;
end;

但是当我尝试进入新行时我会收到错误

ORA-04091: table FIRSTAPP.MESSAGES is mutating, trigger/function may not see it ORA-06512: at "FIRSTAPP.MESSAGES", line 2 ORA-04088: error during execution of trigger 'FIRSTAPP.MESSAGES'

我该怎么做？（'aaa'仅用于测试目的）提前谢谢。

Answer 1

不要更新，只需指定新值即可。但是你需要一个BEFORE触发器才能工作，你不能修改AFTER触发器中的新行：

create or replace trigger "MESSAGES_T1"
  BEFORE insert on "MESSAGES"
  for each row
begin
  :new.short_mess := 'aaa';
end;
/

在pl / sql Trigger中更新

1 个答案: