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Unique Constraint with Multiple NULLS

From: abombss <abombss_at_comcast.net>
Date: Tue, 30 Dec 2003 22:21:54 -0600
Message-ID: <EvidnajeirR702-iRVn-hQ@comcast.com>


What is the SQL-92 standard for allowing multiple NULL values within a unique constraint?

Since NULL is the absence of value I would think that multiple NULLS within a unique constraint would be allowed, however the RDBMS disagrees. Shouldn't a constraint only be concerned with values, not non-values?

Besides a trigger is there any other reasonable way to enforce this behavior if the RDBMS does not support it?

Thanks,

Adam Received on Tue Dec 30 2003 - 22:21:54 CST

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