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From: "Marshall  Spight" <marshall.spight@gmail.com>
Newsgroups: comp.databases.theory
Subject: Re: Database design, Keys and some other things
Date: 27 Sep 2005 09:57:59 -0700
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JOG wrote:
> > " The claim was made that the real world didn't contain
> > predicates that included artificial keys. So I guess that
> > means VIN, bank account number, and SSN are supernatural! Spooky!"
>
> Marshall,
>
> You have rather misunderstood. Noone has made any such claim the real
> world doesn't contain artificial identifiers such as VIN's and SSN's.

You said "The real world is stating a predicate such as [...]
NOT 'There is a car [...] with an invisible universal id of 24."
I took your "invisible universal id" to be a reference to
artificial identifiers. If you're saying artificial identifiers
are okay but invisible universal ids are not, I'm not clear
what the distinction is.


> The claim was that if you are modelling the real world you should not
> have to add new imaginary keys, you're encoded predicate pretending as
> though they were properties of the real world statement, just for the
> database to work. It's a hack.

When you say it's a hack, do you mean that there are problems with
the appoach, and that there are better ways to do it that don't
have those problems? Can you state what the problems are, and
what the better approach is?


Marshall