Re: inverse OR distributive law?

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От Tom Lane
Тема Re: inverse OR distributive law?
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Msg-id 9434.1126753444@sss.pgh.pa.us
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Ответ на inverse OR distributive law?  (Tatsuo Ishii <t-ishii@sra.co.jp>)
Ответы Re: inverse OR distributive law?  (Peter Eisentraut <peter_e@gmx.net>)
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Tatsuo Ishii <t-ishii@sra.co.jp> writes:
>  * process_duplicate_ors
>  *      Given a list of exprs which are ORed together, try to apply
>  *      the inverse OR distributive law.

> Anybody enlighten what "inverse OR distributive law" is?

Well, it's defined right above that:
* The following code attempts to apply the inverse OR distributive law:*        ((A AND B) OR (A AND C))  =>  (A AND (B
ORC))* That is, locate OR clauses in which every subclause contains an* identical term, and pull out the duplicated
terms.

I'm not sure that "inverse OR distributive law" is standard terminology,
but I believe the implication in the other direction is usually called
the "OR distributive law".  Anyone know of better terminology?
        regards, tom lane


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