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_at_comcast.com>
What is the SQL-92 standard for allowing multiple NULL values within a unique constraint?
Date: Tue, 30 Dec 2003 22:21:54 -0600
Message-ID: <EvidnajeirR702-iRVn-hQ_at_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 Wed Dec 31 2003 - 05:21:54 CET