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Re: One Ring to Bind Them

From: Anthony W. Youngman <wol_at_thewolery.demon.co.uk>
Date: Fri, 18 Jun 2004 18:21:11 +0100
Message-ID: <jJnvJwDHSy0AFw$a@thewolery.demon.co.uk>


In message <c9GdnW9YiKJkSlDd4p2dnA_at_comcast.com>, Laconic2 <laconic2_at_comcast.net> writes
>Was: In an RDBMS, what does "Data" mean?
>
>"Eric Kaun" <ekaun_at_yahoo.com> wrote in message
>news:wekzc.25516$Dh6.9215_at_newssvr31.news.prodigy.com...
>
>> This is, more than anything, the philosophical divide between relational
>and
>> Pick folks. The more rules, the more they should be kept OUT of the
>> application code. "Application" means just that: a judicious application.
>Of
>> what? Rules. Application != definition, just as implementation !=
>> specification.
>
>It isn't just the Pick folks. The OO folks also feel that the business
>rules belong encapsulated inside the objects that "really know what's going
>on", as opposed to formalized as metadata and shared the same way data is
>shared.

Yes, but relational formalises metadata INTO data. Once it's in an RDBMS it's no longer metadata, because the rdbms doesn't understand any meaning in it and can't take advantage of that meaning so it's just data.

The ordering in a list is metadata. Convert that into a set to put into an rdbms and ORDER is now just a meaningless (as far as the db engine is concerned) bit of data.

That's where MV and OO fundamentally differ. They try to *avoid* converting metadata to data, so that the db engine can be intelligent and take advantage of it to optimise things.

Cheers,
Wol

-- 
Anthony W. Youngman - wol at thewolery dot demon dot co dot uk
HEX wondered how much he should tell the Wizards. He felt it would not be a
good idea to burden them with too much input. Hex always thought of his reports
as Lies-to-People.
The Science of Discworld : (c) Terry Pratchett 1999
Received on Fri Jun 18 2004 - 12:21:11 CDT

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