Re: foundations of relational theory?

"Anthony W. Youngman" <thewolery_at_nospam.demon.co.uk> wrote in message news:BhNnjiArEal$EwOo_at_thewolery.demon.co.uk...
> In article <bn33eu$12j0$1_at_gazette.almaden.ibm.com>, Paul Vernon
> <paul.vernon_at_ukk.ibmm.comm> writes
> >"Dawn M. Wolthuis" <dwolt_at_iserv.net> wrote in message
> >news:6db906b2.0310202027.58324c36_at_posting.google.com...
> >>
> >> I'm likely just getting old, Paul, but I'm not tracking with you on
> >> this question. What about my statement gives you a hint that if
> >> everything else is equal then an MV system will be less useful and
> >> just what is the everything else? You mean if someone has the same
> >> number of dollars to sink into an MV syste as an RDBMS system, then
> >> the MV system will be less useful? Why?
> >
> >Because a MV system is more complex (contains more constructs), for no
extra
> >power than a relational system.
>
> Except that we need far FEWER tables than you do.

But we only need tables and no extra concepts. The relational model needs fewer constructs/concepts than other models. That we end up with more instances of the concepts in a given system, is a *positive* reflection of the model.

> That means that MV is
> more SIMPLE than a relational system. How many tables do you need to
> model an invoice?

Wrong question. The question is, how many *concepts* do you need to model an invoice?

> In a well designed MV system we will have just *one*
> FILE, that maps EXACTLY to your invoice view.

But a FILE is more than just a set of tuples (aka a table). It is a more complex concept.

> All your integrity enforcement (cascading delete, can't save order
> detail without matching order, etc etc etc) just comes as "part of the
> package" with MV.

Agreed, but that is not a benefit. Constraints are a single concept in the relational model. We don't distinguish between referential integrity and other constraints.

> By the way, there is *scientific* *proof* that you're wrong in assuming
> that a dollar spent on MV buys less than a dollar spent on relational.

It that buys less in 'the future' or 'on average weighted over all possible futures'

The second could conceivably be answered by science, I'm not sure that the first could even in principle.

> Admittedly there is precious little proof, but what little there is came
> to the conclusion that a dollar spent on MV bought the same as two
> dollars spent on relational!

So marketing surveys are *scientific* *proof*, hey. Wow.

[snip]
> And nor do we. The MV model (properly used) treats all entities as
> equal. What it does NOT do is treat

> attributes as equal to the entity they describe (which relational does).

?

> Relational also treats relations as equal to their entities ...

??

[snip]
> Well, from reading Fabian (and I'd include others in this too), I came
> to the conclusion that he is incredibly blinkered and bigoted, he has a
> closed mind, and if he can't understand what you are saying he won't try
> to work out where you're wrong - he'll simply slag you off as deluded.
>
> That would be okay if he's right,

Ah, you've got it.

> but what's the point of trying to
> understand him if he can't be bothered to understand you?

I do sympathise, but from his point of view, I suspect he doesn't feel he has the time to spend to understand (i.e. *educate*) you on a one to one basis. Plus you get a bit world weary after doing it again and again and again.

It's debatable whether not responding would be a better strategy than responding with stuff like 'Your are an idiot'. I certainly think it is little value in publishing such exchanges as he sometime does on his site.

Concentrating on 'educating' the more prolific (I'm not sure I should say 'more respected'), such as in this exchange http://www.dbdebunk.com/page/page/766119.htm, is a better bet in my book. However, I would agree that his style of persuasion is not to everyone's tastes...

> In those
> circumstances the only option open is to assume that he must be wrong.
> Since he has no interest in identifying the flaws in your argument (as
> opposed to you), then the only tenable conclusion is there are no flaws.
> Ergo, it's him that's wrong, not you.

If your arguments we novel and well constructed, then he might have more interest .

Regards
Paul Vernon
Business Intelligence, IBM Global Services Received on Wed Oct 22 2003 - 14:09:29 CEST