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Date: Mon, 06 Jun 2005 16:55:21 +0100
From: Paul <paul@test.com>
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Newsgroups: comp.databases.theory
Subject: Re: Does Codd's view of a relational database differ from that ofDate&
 Darwin? [M.Gittens]
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Xref: dp-news.maxwell.syr.edu comp.databases.theory:31257

paul c wrote:
> i'd like to know what problem the never-ending arguments about nulls are
> aimed at.  in mundane applications at least (which i think is where most
> people spend their time), what is the problem with using empty strings
> for unknown names or zeroes for unknown number values? 

Because the empty string or zeros might also be valid values.

But I guess the principle stands: you could use -1 or "ZZZ" or some
other value that would never be valid. This is really just user-defined
domains lite though, because it means you have to manually set the
behaviour each time you use an aggregate function, rather than the
aggregate function knowing automatically what to do with these special
values.

> i'd rather see a debate about something rather than literally 'nothing',
> say second-order predicate calculus.
> 
> (don't want to be another troll but can't resist - sometimes i wonder if
> all the null talk here and seemingly everywhere else isn't just another
> big hoax, like the OO and XML ones, foisted on the world by coders or
> kibitzers from outside fields who aren't happy with their procedural lot
> in life, not to mention middlemen who see money in it.)

I think it's a big issue because there doesn't seems to be much
consensus on it, even amongst database theory bigwigs. Maybe there is
some theoretical significance to it, but maybe it's just a subjective
software engineering thing that doesn't really have a right or wrong answer.

I think it will always be a standard database flamewar topic.

Paul.