Re: PRIMARY KEY on a *group* of columns imply that each column is NOT

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).