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	Mon, 6 Dec 1999 20:14:56 -0500 (EST)
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To: Gary Stainburn <gary.stainburn@ringways.co.uk>
cc: "'Pgsql Interfaces'" <pgsql-interfaces@postgreSQL.org>
Subject: Re: [INTERFACES] locking on database updates 
In-reply-to: Your message of Mon, 6 Dec 1999 17:16:27 -0000
	<01BF400D.C8C88440@garys.ringways.co.uk>
Date: Mon, 06 Dec 1999 20:14:21 -0500
Message-ID: <20458.944529261@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Gary Stainburn <gary.stainburn@ringways.co.uk> writes:
> My question is this.  Is there a safe way of retrieving the next
> number from the parameter table in such a way that the same number
> cannot be retrieved twice.

Use a SEQUENCE object for each "parameter table".  This gives you 
a well-tested, efficient generator mechanism.  It may be "auto
generated" but you do have the option of resetting the sequence's
nextval and so forth, so I don't see that there is a good reason
to build a SEQUENCE substitute by hand.

			regards, tom lane