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Message-ID: <409D8E48.3070805@familyhealth.com.au>
Date: Sun, 09 May 2004 09:50:00 +0800
From: Christopher Kings-Lynne <chriskl@familyhealth.com.au>
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To: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: elein <elein@varlena.com>,
	PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Adding MERGE to the TODO list (resend with subject)
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> What does the MERGE command do?  I have never heard of it, so I doubt
> someone is working on it.

It is basically the SQL standard version of MySQL's REPLACE syntax.  It 
does an update-else-insert set.  However, the trick is that it uses some 
sort of next key locking to ensure that it cannot fail.  Something that 
is impossible to do in PostgreSQL at the moment. Nested transactions 
will help, however.

Chris