Re: Database design, Keys and some other things

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Sat, 01 Oct 2005 22:30:56 +0200
Message-ID: <433ef152$0$11068$e4fe514c@news.xs4all.nl>

paul c wrote:
> mAsterdam wrote:

>> paul c wrote:
>>> mAsterdam wrote:
>>>
>>>> ... When designing a database, we assume a closed world for
>>>> the database under design. Aren't you sugessting we
>>>> work within that same specific closed world when
>>>> designing it?
>>>
>>> Yes.
>>>
>>> Also that this makes the notion of "surrogate" meaningless within the 
>>> CWA.
>>
>> Well, when you are designing that big a database,
>> you are right of course. For all other databases not, though.

>
> That reminds me of something I read: "the purpose of metaphysics is to
> correct metaphysics", which I think I can justify only by giving a
> longer reply.
>
> I'd say the db only has to be as big as having one more attribute than
> the smallest possible db. Would think this would include most databases.
>
> I'm assuming that by "smallest" we mean a db that only the empty set as
> attribute even though there could be many differently-named relations
> within it.

I don't understand. It may be a nice exercise to explain some concepts, but can such a database hold relevant facts for anyone?

The determination of what facttypes will be in the database is defining its closed world (CW). Unless you a designing a database for database design, 'facttypes' will not be in the databases' CW - it will be in the designers CW. Received on Sat Oct 01 2005 - 15:30:56 CDT