Re: Poll: What percentage advantage are RDBMS vendors taking of the RM?

From: <lauri.pietarinen_at_atbusiness.com>
Date: 29 Jun 2005 23:48:08 -0700
Message-ID: <1120114088.909668.301220_at_g14g2000cwa.googlegroups.com>


mountain man wrote:
> <lauri.pietarinen_at_atbusiness.com> wrote in message
> news:1119567400.729054.215810_at_g44g2000cwa.googlegroups.com...
> > mountain man wrote:
> >
> > I think it's like asking "How much, as a percentage out of 100,
> > was calculus "realised" in the 18th century by the current
> > mathematicians", such as Lagrange and Euler. They surely made lot's of
> > important discoveries, but still further important work was to come
> > after the "cleaning up" of Analysis by the likes of Cauchy, Gauss and
> > Riemann. For instance there was not even a proof for the binominal
> > theorem when n is not an integer greater than zero until Gauss gave
> > one. 1)
>
>
> > So, from the perspective of the 18th century the answer would have
> > maybe been close to 80, but we now know that they had barely scratched
> > the surface!
>
>
> So is this an 80%, with reservations that this 80% will in 200
> years time be viewed as 10%?

Who knows? We will all be dead by then, to quote a famous American president.

>
> > Likewise, since the RM is a mathematical theory, we don't really know
> > where it will lead us in the future.
>
>
> Is there only one Relational Model (ie: as espoused by Date)
> or are there variant interpretations thereof, such as there exist
> a variety of "intepretations" of quantum theory in physics?

Over time things will settle. It took a long time to find a good definition for x! (i.e. the factorial for non-integer numbers, e.g. (4.5)! ) but an elegant interpretation was
found.

As for the variant interpretations, some of them result from "fixing the theory around the practice" as with duplicate rows. I can't seriously see that as an interpretation.

Others, such as allowing or not allowing nested relations, will - and have been - settled over time. Anyway, if we restrict the model not to include nested relations, we are not losing that much power in practice.

Do you have other other interpretations in mind?

>
> Also, it seems as though some people say it will evolve,
> such as yourself, yet others here assert it is an unchanging
> principle that does not change. At least we agree things
> evolve.
>

Surely the basic principles and conclusions of Newton and Leibniz still hold regarding Calculus inspite of the refinements made to it over time. An integer is still an integer albeit having been defined in various ways over the centuries. It's just that we will discover new ways to refine the definition and to build on it.

So I believe that the very basic core will remain but it will be refined (and a refinement does not mean adding support for duplicate rows). And there will be more and more discoveries around this core, such as real and complex numbers in the case of refining the concept of a number.

>
> > However, it is important to try
> > to keep the theory "clean" even though the practical consequences are
> > not obvious at the time or might even cause some backsteps. The
> > products (such as DB2, Oracle and SQLServer) are chained to their
> > current user base and they don't really have a way out. They can only
> > go towards increased complexity.
>
> They exist, it seems to me, as clear examples of incarnation
> of the RM, whether or not incomplete from the perspective
> of theory. There may be pathways towards simplicity.

What incarnations do you have in mind?

>
>
> What advances in the theory of the RM have there been since
> Codd's first paper, from the theory side? Are they numerous
> or singular?
>

  • Normalisation theory (strictly speaking not part of the RM)
  • Better understanding of transformation rules
  • Also lots of new theory regarding how to *implement* the RM, maybe not directly related to RM but at least inspired by it (optimisation, indexing strategies, locking).

Some advances, such as sub tables, have turned out not to be very useful (they were inspired by the OO-model).

I would not know how to answer your question with any great authority, but I hope you get the picture.

To be frank, I am not totally comfortable with the idea of a group of people acting as the guardians and gate keepers of the RM, but I am much less happy of all the strange things proposed for data management, such as XML.

"All models are wrong, but some are useful"

So it is not really a question of if the RM is "God's answer to data management" but the question is "is it useful?" We don't know if Analysis is "correct" but somehow, mysteriously, it is useful for calculating many practical things. Logic, as a branch of mathematics, as turned out to be immensly useful. The RM is based on logic and hence can borrow from the results of 2500 years of work.

regards,
Lauri Pietarinen Received on Thu Jun 30 2005 - 08:48:08 CEST

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