Date: Tue, 17 Jul 2007 16:48:44 -0400
From: Andrew Sullivan <ajs@crankycanuck.ca>
To: pgsql-sql@postgresql.org
Subject: Re: data dependent sequences?
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On Tue, Jul 17, 2007 at 12:23:21PM -0600, Stuart wrote:
> 
> Except that the value does matter outside of the database and thus
> needs to be remembered.  It is not used for ordering at all.

If you have two rows of data, where one column is data that varies as
a function of the data in some other column, then what you have is
data from two different tables, and not one table at all.  At least,
according to the rules of normalisation I know.

My best guess, however, is that you're trying to implement a poor
requirement.  My bet is that if you dig harder, you'll find out what
the requirement _really_ is, and then you won't have to implement
what sounds like a bad idea.

A

-- 
Andrew Sullivan  | ajs@crankycanuck.ca
However important originality may be in some fields, restraint and 
adherence to procedure emerge as the more significant virtues in a 
great many others.   --Alain de Botton