Re: The term "theory" as in "database theory"

On Jan 26, 2:33 pm, Kenneth Downs <knode.wants.t..._at_see.sigblock> wrote:
> dawn wrote:
> > I have been working on a question related to the term "theory" and
> > decided I first should get a better idea of what this term means to
> > others. Below is the dictionary.com list of definitions. Which of the
> > following comes closest to the use of the term "theory" in this ng as
> > in "database theory", or is there another someone wants to provide?
> > Thanks in advance. --dawn
>
> >>From dictionary.com
>
> > "1. a coherent group of general propositions used as principles of
> > explanation for a class of phenomena: Einstein's theory of relativity.
>
> Unsuitble. A database is not a phenomenon whose principles need to be
> discovered, as for instance the phenomenon of gravity is the subject of
> Einstein's theory of relativity. A database is a man-made thing whose
> principles are crafted by the human mind to accomplish human goals.

Agreed.

> > 2. a proposed explanation whose status is still conjectural, in
> > contrast to well-established propositions that are regarded as
> > reporting matters of actual fact.

> See above.

Agreed. This gets at one of my reasons for asking. I have read Date, Pascal and others refer to Occam's razor related to relational theory. For example, see http://www.dbazine.com/ofinterest/oi-articles/pascal12 and search the page for Occam. Although Occam's razor cannot be proven, it is in the belief system of many. So, let's take it as a given (even if it isn't). Doesn't Occam's razor refer to the above two meanings of "theory" rather than to anything related to "database theory"?

Maybe this has all been dispelled before, but I heard it again recently and really want to put this one to rest, if feasible. Are people in this forum at least agreed that Occam's razor has nothing to do with relational theory?

> > 3. Mathematics. a body of principles, theorems, or the like, belonging
> > to one subject: number theory.See above.
>
> > 4. the branch of a science or art that deals with its principles or
> > methods, as distinguished from its practice: music theory.
>
> Now we have something, a description of a human pursuit. This makes as much
> sense as #5 below.
>
> > 5. a particular conception or view of something to be done or of the
> > method of doing it; a system of rules or principles.
>
> Sounds the same as 4, generally speaking.

OK, that was my impression too. So, one person might have 2VL in their theory and another might have 3VL, right? How would one judge whether one was better than another? I would think that would be by applying each system of rules along with some means of measuring which system produces better results in various areas. Judging database theories would be much like judging software products - what features does it provide, what quality requirements does it meet, etc. Does that make sense?

> > 6. contemplation or speculation.
> > 7. guess or conjecture.

>"Ha! We'll get lots of wise-cracks on these two!

Sometimes my statements align with 4 & 5, in which case they could be judged by what features are present and which are not. Sometimes I get responses or give statements that are more in the 6 or 7 category. But if someone guesses that that relational theory is better for xyz in the long term and I guess it is not, then a comparison of features (which we might do to judge database theory as mentioned above) is not sufficient because we can disagree on which approach is more feature-rich or meets the requirements best. We actually need to know which requirements we are aiming for and then perhaps collect emperical data, not just think "hey, it seems to me that relational theory should provide us with databases that are easier to maintain with quality data over the long term than other databases." But when I bring up emperical data, some indications are that this is outside the scope of database theory.

So, I'm confused on how others are thinking one judges whether they have a good "database theory." There seem to be some who indicate that the judgment of whether a theory is good or not lies in the mathematics of the theory. I do not understand how this could possibly be the case (and that might be why I have been told that I do not appreciate theory). The mathematics of a theory could be absolutely beautiful and the resulting "database theory" could be awful, right? I do understand that some features on our list where we could do comparisons include "provability" and "query symmetry" but these are simply items on our requirements list, not the only items on the list nor the only measures of a theory. The feature list for databases (and DBMS's) is huge, and similarly for related database theory, I would think. One requirement I have for database theories, for example, is that they lead to implementations that are a "big bang for the buck" for companies using those products.

I also am not sure whether sometimes when a person writes "theory" they are referring only to the mathematics portion of the rules. For example, are "produce a nightly backup to disk" and "have a real-time operational database that is a duplicate of the OLTP database" possible statements in a "database theory" or not? Why or why not?

Thanks for the discussion on this. --dawn

> --
> Kenneth Downs
> Secure Data Software, Inc.
> (Ken)nneth_at_(Sec)ure(Dat)a(.com)
Received on Fri Jan 26 2007 - 23:05:18 CET