Re: In an RDBMS, what does "Data" mean?
Date: Sat, 29 May 2004 14:25:32 -0500
Message-ID: <c9ao3q$a0q$1_at_news.netins.net>
"Tony" <andrewst_at_onetel.net.uk> wrote in message
news:c0e3f26e.0405290915.17c5cb88_at_posting.google.com...
> "Anthony W. Youngman" <wol_at_thewolery.demon.co.uk> wrote in message
news:<5zLJHbCQS4tAFwWy_at_thewolery.demon.co.uk>...
> > In message <40b74ea7$0$1049$ed2619ec_at_ptn-nntp-reader02.plus.net>, Paul
> > <paul_at_test.com> writes
> > >Dawn M. Wolthuis wrote:
> > >>> Newtonian Dynamics assumes certain axioms, which we now know to be
> > >>>slightly wrong.
> > >> If talking about mathematical axioms, they are not right or wrong --
> > >> they just are. It is the use of those axioms in some setting or
> > >>another that could be inappropriate, not useful, or lead one to draw
> > >> incorrect conclusions due to applying a poor mathematical analogy
> > >>(metaphor) to the situation.
> > >
> > >Well, OK, when I say the axioms are wrong I mean that the axioms don't
> > >quite give a theory on which we can base an accurate model of reality.
> > >(Though they may be good enough for an approximate model of reality).
> > >
> > >> So the mathematics is right, but the science is wrong -- and I think
> > >> that is a major point of this thread.
> > >
> > >My point is that the DBMS is only concerned the mathematical part, and
> > >theory proves that it does it perfectly. The science part is beyond the
> > >scope of the DBMS - making sure that is OK is up to the database users.
> >
> > So, what you're saying, basically, is every time the users have a
> > problem "it's an implementation thing", despite the fact that it may
> > well be down to a screwy axiom? What you're saying is that you couldn't
> > care less whether your axioms are correct or not?
> >
> > Or, to put it more bluntly, you don't know whether your model correctly
> > models the real world, and you don't care whether your model correctly
> > models the real world, yet you loudly trumpet that it is the only model
> > that can model the real world ... excuse me while I puke ...
> >
> > Surely you owe it to your users to at least try and make sure the
> > foundations of your theory are securely anchored in the real world,
> > rather than building castles in the air and then blaming users when
> > their real applications built on those castles come tumbling to earth in
> > an awful heap.
> >
> > Sorry, I don't want this to come over as nasty, but that last paragraph
> > of yours that I quoted is basically just abdicating any responsibility
> > on the part of mathematicians as to whether the theory is useful in any
> > shape or form whatsoever; and worse, blames the users for incompetence
> > if they can't get it to work.
> >
> > Cheers,
> > Wol
> > You just don't get it, do you Wol? No matter how many times people > try to explain it to you it just doesn't sink in. The relational > model is NOT a model of "the real world" and it therefore doesn't have > to correspond to the real world. It is a model of data, which is an > abstract concept.
and I just responded to Alfredo who said that data were facts and I thought for sure the idea was that these facts corresponded to reality.
I don't have a problem with the mathematical theory termed "relational theory" except when the words used are those used in set theory and the definitions are different ;-)
If there is a tight mathematical definition of "data" within relational theory, then that's great, but it is not the commonly used definition, I suspect. It is in the leap from doing relational theory to thinking that the application of such theory is the best approach to storing/retrieving propositions using computers by a business -- that is where there is a rather significant leap of faith. That connection is NOT science, although we could conceivably set up some experiments to collect a bit more information about whether it is better than some other approach. I'm not opposed to faith, but we need to call it what it is. There is mathematical relational theory and then a leap of faith in the use of relational theory for anything.
> Now, when someone uses the relational model to build a database > corresponding to some real world thing, say a payroll system, then it > is up to the database designer (not the relational model) to ensure > that what he builds corresponds to the reality he is building it for.
And perhaps that person opts out of using (at least all of) relational theory and that's fine, right?
> To go back to your favourite analogy (apologies everyone), it is like > saying that algebra was responsible for the shortcomings of Newton's > model of planetary motion. But it wasn't the algebra that "got it > wrong", it was Newton's application of it.
Agreed!
> The relational model
> corresponds to algebra in this analogy,
YES!
> not to Newton's model of the
> solar system - that corresponds to a specific database design.
wrong -- that corresponds to the use of relational theory at all while working with computers. It is not the specific implementation only that could be wrong -- it is the use of this theory AT ALL related to "data processing" that COULD BE wrong (I don't think it is entirely irrelevant, but there is nothing that proves its relevance except where "the proof is in the pudding" -- scientific observation, for example).
> Einstein didn't invent a better algebra, he designed a better model > using the SAME algebra - like a later designer designing a better > payroll database, but still using the same RDBMS.
No, like a later database theorist designing a graphical theory or a functional theory that is better than the relational theory before it.
smiles. --dawn Received on Sat May 29 2004 - 21:25:32 CEST