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Re: Any way to do "unique or null"?

From: Reid Lai <reidlai_at_hk.super.net>
Date: Fri, 11 Sep 1998 14:14:44 +0800
Message-ID: <35F8BFD4.9EBF1D95@hk.super.net> 





You should use BEFORE INSERT trigger to do so instead of constraint.



Roy Smith wrote:



> I've got a column which I want to allow to be null, but if there is a


> value in it, I want to ensure that value is unique amongst the non-null


> entries.  Can a constraint be used to do this?


>


> --


> Roy Smith <roy_at_popmail.med.nyu.edu>


> New York University School of Medicine





Received on Fri Sep 11 1998 - 01:14:44 CDT












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