Re: PRIMARY KEY on a *group* of columns imply that each column is NOT - Mailing list pgsql-general

From Stephane Bortzmeyer
Subject Re: PRIMARY KEY on a *group* of columns imply that each column is NOT
Date
Msg-id 20050427150017.GB2740@nic.fr
Whole thread Raw
In response to Re: PRIMARY KEY on a *group* of columns imply that each  (Scott Marlowe <smarlowe@g2switchworks.com>)
Responses Re: PRIMARY KEY on a *group* of columns imply that each column is  (Marco Colombo <pgsql@esiway.net>)
List pgsql-general
On Wed, Apr 27, 2005 at 09:36:57AM -0500,
 Scott Marlowe <smarlowe@g2switchworks.com> wrote
 a message of 18 lines which said:

> Often the best bet here, btw, is to declare it not null then use
> something other than null to represent null, like the text
> characters NA or something.

Yes, but it defeats the purpose of NULL. And what should I use as a
"pseudo-NULL" value for INET? 127.0.0.1? 0.0.0.0? Special values are
well-known for the problems they raise. That's why many languages have
NULL-like solutions (None in Python, undef in Perl, Maybe types in
Haskell, etc).


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