Skip site navigation (1) Skip section navigation (2)

Re: Unique indices and nulls

From: Roland Roberts <roland(at)astrofoto(dot)org>
To: pgsql-novice(at)postgresql(dot)org
Subject: Re: Unique indices and nulls
Date: 2002-09-11 17:21:28
Message-ID: m23csg1lyf.fsf@kuiper.rlent.pnet (view raw or flat)
Thread:
Lists: pgsql-novice
>>>>> "Josh" == Josh Berkus <josh(at)agliodbs(dot)com> writes:

    Josh> All DBAs are guilty of, to a lesser or greater degree, using
    Josh> NULL to represent "None", even though NULL actually means
    Josh> "unknown" according to the SQL spec.  The rest of the SQL
    Josh> spec is designed to support NULLs as "unknown", so this can
    Josh> lead to problems in application.  Like yours.

This is a good point, and since I know the range of values which can
go into those columns, it is easy to pick something to use as
representing "none."

roland
-- 
		       PGP Key ID: 66 BC 3B CD
Roland B. Roberts, PhD                             RL Enterprises
roland(at)rlenter(dot)com                     76-15 113th Street, Apt 3B
roland(at)astrofoto(dot)org                       Forest Hills, NY 11375

In response to

pgsql-novice by date

Next:From: reshat.sabiq.1Date: 2002-09-11 17:36:39
Subject: Changing default user's passwd
Previous:From: Terry YaptDate: 2002-09-11 17:20:32
Subject: Re: Strange situation with two tables.

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group