如何检查是否在PL/SQL BEFORE UPDATE触发器中显式指定了列值? [英] How to check if a columns value was explicitly specified in a PL/SQL BEFORE UPDATE trigger?

问题描述

有没有办法知道在PL/SQL BEFORE UPDATE触发器中显式更新了哪些列?

Is there a way to tell which columns were explicitly updated in a PL/SQL BEFORE UPDATE trigger?

例如:仅当UPDATE语句未为该列明确指定值时，我才想设置:new.last_modified_by := USER.

For example: I want to set :new.last_modified_by := USER only if the UPDATE statement did not explicitly specify a value for this column.

推荐答案

使用UPDATING函数:

if updating('LAST_MODIFIED_BY') then 
...
end if;

更多详细信息在手册中: http://docs.oracle. com/cd/E11882_01/appdev.112/e25519/triggers.htm#BCFIDDBB

More details are in the manual: http://docs.oracle.com/cd/E11882_01/appdev.112/e25519/triggers.htm#BCFIDDBB

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