Andreas Pflug <pgadmin@pse-consulting.de> writes:
> Tom Lane wrote:
>> This can already be done by comparing old and new values, no?
>>
> No, this is not the case.
> UPDATE foo SET x=x, y=y
> is different from
> UPDATE foo SET y=y
> if triggers maintaining x are involved.
Only for what I would call extremely weird semantics of the triggers.
If a trigger preceding yours did the same action (assigned x to itself),
would you consider that something you needed to track? If so, how would
you find out about it? You couldn't.
If you want me to believe that the above is an important requirement,
you'd better convince me that it's sane, because I don't think so.
regards, tom lane