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Home -> Community -> Usenet -> comp.databases.theory -> Re: A pk is *both* a physical and a logical object.

Re: A pk is *both* a physical and a logical object.

From: Brian Selzer <brian_at_selzer-software.com>
Date: Fri, 20 Jul 2007 02:42:42 GMT
Message-ID: <CiVni.9620$eY.8268@newssvr13.news.prodigy.net>

"Nis Jørgensen" <nis_at_superlativ.dk> wrote in message news:469f66a0$0$90264$14726298_at_news.sunsite.dk...
> Brian Selzer skrev:
>
>> The schema of a database describes a set of possible database values,
>> each
>> of which represents a complete description of a situation that may occur,
>> and the body of a database, the actual database value, represents a
>> complete
>> description of the situation that is actually occuring. In this context,
>> a
>> world is a situation, an instance of the universe--a particular set of
>> circumstances that can or do obtain. An update clearly designates which
>> of
>> the possible database values is now the actual database value, and since
>> there is a bijective mapping between the set of all possible database
>> values
>> and the set of all possible worlds, it stands to reason that an update
>> causes a possible world to become the actual world.
>
> I guess next you are going to tell us that nulls are really an attempt
> at modelling quantum physics. Or was that transactions?
>

Are they?

> Nis
Received on Thu Jul 19 2007 - 21:42:42 CDT

Original text of this message

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