　　今天，通过MS SQL Server远程修改Oracle一张表的数据时引发了ORA-04091的错误。错误信息如下：

链接服务器"ORCL61"的 OLE DB 访问接口 "MSDAORA" 返回了消息 "

ORA-04091: table SZKINGGO.TAWB_AWB is mutating, trigger/function may not see it

ORA-06512: at "SZKINGGO.PROC_UAGENTEXPENSE", line 26

ORA-06512: at "SZKINGGO.TRIG_TAWB_AWBCHARGE", line 166

ORA-04088: error during execution of trigger 'SZKINGGO.TRIG_TAWB_AWBCHARGE'

ORA-06512: at "SZKINGGO.TRIG_TAWB_AWB", line 91

ORA-04088: error during execution of trigger 'SZKINGGO.TRIG_TAWB_AWB'

"。

消息 7343，级别 16，状态 4，过程 PROC_AWB，第 251 行

链接服务器 "ORCL61" 的 OLE DB 访问接口 "MSDAORA" 无法 UPDATE 表 "[MSDAORA]"。

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首先查询下ORA-04091错误的相关信息：

[oracle@lonion ~]$ oerr ora 04091

04091, 00000, "table %s.%s is mutating, trigger/function may not see it"

*Cause: A trigger (or a user defined plsql function that is referenced in this statement) attempted to

look at (or modify) a table that was in the middle of being modified by the statement which

fired it.

*Action: Rewrite the trigger (or function) so it does not read that table.

根据错误的描述，可以得知触发当前表的触发过程中又对该表进行了SELECT或DML的操作。为了避免这个错误，在写触发器的时候，尽可能的避免对当前表的引用。

我当前问题出现ORA-04091的原因是：当前触发器调用了存储过程PROC_UAGENTEXPENSE，而PROC_UAGENTEXPENSE中又对引发触发的表进行了SELECT操作。

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ORA-04091