Re: Does Codd's view of a relational database differ from that of Date & Darwin? [M.Gittens]
From: Paul <paul_at_test.com>
Date: Sun, 05 Jun 2005 11:20:37 +0100
Message-ID: <42a2d1f5$0$1694$ed2e19e4_at_ptn-nntp-reader04.plus.net>
>
> It would keep the meta-model simpeler. But that's not the only way to
> model partial information w/o null values and in many cases the worst
> way to do it.
Date: Sun, 05 Jun 2005 11:20:37 +0100
Message-ID: <42a2d1f5$0$1694$ed2e19e4_at_ptn-nntp-reader04.plus.net>
Jan Hidders wrote:
>> Modelling holes in information is straightforward >> with the use of nulls. You either have them, or >> you dont. You could probably replace then with >> a value, say x, but what would this gain?
>
> It would keep the meta-model simpeler. But that's not the only way to
> model partial information w/o null values and in many cases the worst
> way to do it.
What are better ways to do it? Decomposing relations into several
smaller ones as described here?:
http://www.hughdarwen.freeola.com/TheThirdManifesto.web/Missing-info-without-nulls.pdf
Why is the "special values in the domain" method inferior to other methods?
Paul. Received on Sun Jun 05 2005 - 12:20:37 CEST