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Re: In an RDBMS, what does "Data" mean?

From: Anthony W. Youngman <>
Date: Tue, 8 Jun 2004 00:10:34 +0100
Message-ID: <>

In message <kH4wc.5267$>, Eric Kaun <> writes
>> hey man, now you're talkin' but now we want to ask questions of the data,
>> we need to tag some parts, without harming any animals, and there you have
>> it ;-)
>Heh... oh, so you don't give a darn about plants? Speciesist.
>Asking questions is precisely the point of relational, and has been pointed
>out, relational is more egalitarian with respect to what you can ask, in
>that it requires that only relations (and tuples, which are directly
>implied) "tag" the data. Tagging, though, implies a high ratio of text to
>markup - else you end up with the mess that is many XML docs, with a 5:1
>ratio of tags to data. And XML tagging has a limited type system, and
>nothing about constraints.

Relational is more egalitarian about what you can ask (actually, I'm not sure about that, but never mind ...)

But it's like being "politically correct". Sure, you may want to know "how many blokes have a car the same colour as their wife's hair?".

BUT! Do you want to make "all questions equally easy to answer" or do you want to make "common questions easier to answer than unusual ones". If by levelling off the ease of asking questions, you simply make the easier questions harder in order to level the playing field, you're doing your users a very big disservice. Is that what you're trying to achieve?

And with a little bit of thought, you can make nearly ANY question in Pick easy to answer. More to the point, you can PROVE that the system can answer the question easily. Given that relational goes to extreme lengths to separate the logical from the physical, relational actually prevents you from even trying to prove the question is easy, merely saying "you have no choice but to trust the optimiser" :-(


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 Mon Jun 07 2004 - 18:10:34 CDT

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