Re: Unique constraint and NULL values
From: <ctcgag_at_hotmail.com>
Date: 21 Oct 2004 16:23:01 GMT
Message-ID: <20041021122301.861$C2_at_newsreader.com>
Date: 21 Oct 2004 16:23:01 GMT
Message-ID: <20041021122301.861$C2_at_newsreader.com>
"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!)
>
> if i'm creating a UNIQUE constraint, my goal is to disallow values that
> are known to be equal to other known values -- so, it's entirely
> appropriate to not disallow (sorry for the double-negs) unknown values
> (triple-negs?) since there is no known basis for excluding them
But then why does it exclude them when there are other columns present?
Xho
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