Re: Relations as Repeating Groups & Namespaces

"Alan" <alan_at_erols.com> wrote in message news:2i940rFju0m6U1_at_uni-berlin.de...
>
> "Dawn M. Wolthuis" <dwolt_at_tincat-group.com> wrote in message
> news:c9nh8r$i8f$1_at_news.netins.net...
<snip>
> After you've read this book and/or taken two or three
> semesters of graduate level relational database theory, we can talk.

Now, son, did you really want to say that? ;-)

> Note
> that I am a practitioner, not a theorist, which is why, as you may have
> noticed, I supply examples rather than enounce theories and discuss
proofs.

That's just fine -- I've been a practitioner for over a quarter of a century and after you have... ;-)

> Having studied the theory (in exhausting detail), I am content that it is
> internally correct, and can be applied properly to most situations.

"Can be" is not an issue. I think that folks like Date and Celko help the practitioners with various design patterns for handling less-then-obvious implementations and, yes, the relational model, even as implemented in current SQL-DBMS's works. How SHOULD WE do business, is my question. It is obvious that the scope of the relational model is such that it doesn't extend to all best practices within the "data processing" industry. I also suspect, but have not proven, that such things as not permitting lists in the value of an attribute (which has been the case for years with SQL-DBMS's, at least not supporting such with proper operations/functions in the first order predicate logic of the system) are not good ways of doing business. I've seen relational theory in action as well as other a-relational approaches (which do not rise to the level of mathematical theories yet, in general, although some do). Off the top of my head, without adequate research to back this up -- relational approaches seem to be big, heavy, brittle, and expensive while other approaches I have used have been more big bang for the buck.

> Note
> that among scholars, there has been little in the way of major revisions
to
> relational theory.

Yes, I do note that, but that's gonna change and is changing (knock on wood).

> There have been extensions and expansions
> (object-relational), some refinements (EER) as well as some argument as to
> implementation (SQL compliance, E.g.), but no one has said, "Wait a
minute -
> there has been no definitive discussion. We need to clarify some things
for
> everybody."

me for one

> Except by posters to this newsgroup.

I have said these things before the newsgroup and am using this group to learn more and try to figure out the thought processes of those who buy relational theory front to back.

> Like those who insist that
> data is code or functional dependencies are functions :) Sorry- didn't
mean
> to open that can 'o worms again, but I couldn't resist a good elbow jab.

Your forgiven - you are young, so you know everything. ;-)

> But seriously, if you have $90 to spare, you may want to winch up a copy
of
> Elmasri (4th Ed out now). Or maybe hit a campus bookstore and peruse it.
> Bring coffee- there's not much of a plot, and character development is,
> well, not very interesting...

You might be shocked to hear how far I would have to drive to put my hands on a copy of that book shy of buying it. Since I bought the comparably priced Date book, I'll stick with that. I'm taking a break about 1/2 way through it, but I do suspect I have read at least as much as you in the area of relational theory. I'm just slower to catch on, perhaps, and given my experience, I'm not about to buy into the religion without understanding more precisely what is useful and what is not about this theory. Before I had such experience, I was a relational believer myself. Cheers! --dawn Received on Thu Jun 03 2004 - 22:36:41 CEST