Re: Conceptual, Logical, and Physical views of data

From: David Cressey <>
Date: Mon, 12 Sep 2005 14:18:36 GMT
Message-ID: <07gVe.11270$>

"dawn" <> wrote in message

> I've learned plenty from you, David. I suspect you might not suggest
> you have learned anything (positive) from me.

I'm frustrated that I have heard from you over and over again about the glories of Pick and a variety of other
products, without a simple illustrative example that will explain why someone who can use SQL and the RDM to good effect should be interested in the alternative you claim to be superior.

> >From your statement here, I do sense that you think I say "I don't
> understand" when I really do understand, but disagree.


> I find it exceedingly irritating that I don't buy into relational
> theory the way most professionals do.

> All external factors point to
> SQL-DBMS tools as being a good way to do business, including IBM, MS,
> and Oracle and their db customers all investing heavily in these.

I'm glad to see you finally admit this. You've gone on and on about how much IBM invested in one of the MV products you like, but have never, to my knowledge, admitted that IBM makes that investment in addition to (not instead of) investing in the products of the relational class.

> So, why don't I "get it"?

Everything you have said convinces me that your failure to "get it" is NOT due to a lack of intelligence, education, experience, or expertise. What you are expressing is "invincible ignorance".

> It isn't that simple. I still think I'm not "getting it" and you are.
> I would like to wake up at some point and have it all as clear to me
> why all my standard database application data should be modeled
> according to relational theory or, if that doesn't happen, have enough
> understanding of why I disagree that I can give a rationale that is
> more than just "but my experience has been ..." or "but I think ...".

I'm going to repeat what I've said before: I'm no theoretician. If you need a theoretical proof that the relational model is sound, I simply cannot provide that. If you need examples of success stories using RDM from experience, they abound in the industry. My own experiences are meaningful to me, but you have far better examples than mine to observe.

> And I would be very pleased to hear that explanation (although you
> might tell me that you have already provided such -- I really am having
> memory issues).

> > But I have little, if anything, to teach to you.
> You might feel that way, but I have learned quite a bit from you. If
> you say something and I disagree, should I pretend to agree? If I
> don't understand how you arrived at a conclusion and want to, should I
> refrain from asking? I would think your answers to those questions
> would be "no", right?
> > I need not teach you
> > anything that you already know to be true. I cannot teach you anything
> > you already know to be false. What's left?
> I'm hoping you are going to be willing to tell me what you have taught
> others is the difference between a pointer and a foreign key. But then
> I suspect I will have a follow-up question and you will think something
> like "You can't teach that girl anything!" and we will do the same
> dance that you don't enjoy.

The stuff I said was very low level introductory stuff. The sort of thing that would have been learned by people who worked for you on the Oracle projects that you led. I think it's beyond belief that you have not already been exposed to everything I could say on the subject.

All I'm going to suggest is that you go back to some classic work on databases, preferably one that predates the widespread acceptance of the relational model, and read up on the difference between "pinned records" and "unpinned records". I am sure you can, if you will, learn all that you need to learn from that.

> By the way, if you go to any db-related conferences, let me know in
> advance which ones (that goes for others of you too) and maybe an
> in-person meeting would settle this little glitch. I was going to be
> in Orlando right now for an IBM DB2 conference, but couldn't swing the
> logistics. cheers! --dawn

No, I don't attend those conferences. Perhaps I should. But I'm largely retired now, and I don't think it's central enough to my life. Received on Mon Sep 12 2005 - 16:18:36 CEST

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