Re: Unique constraint and NULL values

From: Frank Piron <empty_at_zero.nil>
Date: Fri, 22 Oct 2004 08:14:41 +0200
Message-ID: <opsf9cyrlkm0et4w@news.online.de>

Thu, 21 Oct 2004 11:40:48 -0400 Mark C. Stock <mcstockX_at_Xenquery .com> wrote:

> yes, in theory, the SQL Server approach is more 'pure', but in practice,
> the
> Oracle approach is more practical (i'm starting to sound like yogi
> berra!)

Agreed. IMO the most plausible argument for the Oracle approach is the observation that allowing exactly one row with a null value in a certain column would mean that
1)
The column value is "identifying" the row (unique constraint). 2)
NULL - an undefined value - is an "identifying" value.

which does not make sense for me.

-- 
Frank Piron,
etfrankatkonaddotn
(leftrotate two)

Received on Fri Oct 22 2004 - 01:14:41 CDT