From: Tom Lane <tgl@sss.pgh.pa.us>
To: Bryce Nesbitt <bryce1@obviously.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: UNIQUE, btree index allows duplicate records, if some fields are null
Date: Thu, 09 Feb 2006 14:59:14 -0500
Message-ID: <4118.1139515154@sss.pgh.pa.us> (raw)
In-Reply-To: <43EB9A3B.2080507@obviously.com>
References: <43EB9A3B.2080507@obviously.com>
Bryce Nesbitt <bryce1@obviously.com> writes:
> I have a table with the following:
> "eg_vehicle_event_pkey" PRIMARY KEY, btree (event_id)
> "no_duplicate_events" UNIQUE, btree (thing, other_thing,
> "timestamp", number, other_number)
> The "no_duplicate_events" constraint works fine, but if I insert records
> where
> "other_thing" is null, they all go in without complaint. I can insert as
> many duplicates as I want.
This is per SQL spec. You're imagining that two nulls are considered
equal, which they are not.
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, bryce1@obviously.com
Subject: Re: UNIQUE, btree index allows duplicate records, if some fields are null
In-Reply-To: <4118.1139515154@sss.pgh.pa.us>
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