Re: Codd provided appropriate mathematics ... (was Re: Relational and MV (response to "foundations of relational theory"))

"mountain man" <hobbit_at_southern_seaweed.com.op> wrote in message news:dQRZb.70077$Wa.44456_at_news-server.bigpond.net.au...
> "Dawn M. Wolthuis" <dwolt_at_tincat-group.com> wrote in message
> news:c12ia2$p0l$1_at_news.netins.net...
> > "mountain man" <hobbit_at_southern_seaweed.com.op> wrote in message
> > news:r3%Yb.66336$Wa.13812_at_news-server.bigpond.net.au...
> > > "Neo" <neo55592_at_hotmail.com> wrote in message
> > > news:4b45d3ad.0402181740.42d42bc2_at_posting.google.com...
> > > > Execute("SELECT * FROM BOB WHERE OUTPUT = FALSE");
> > > >
> > > > 19 Records Found:
> > > > "Codd provided appropriate mathematical backing to all of his
claims"
> > >
> > > ...[trim]...
> > >
> > > I'd be interested to hear about this. Empirical
> > > evidence should either exist or not exist. The
> > > "all" word might be troublesome.
> >
> > I have found at least one area where Codd takes a jump mathematically.
> I'm
> > not taking the time right now to get his exact wording, but a summary is
> > this:
> >
> > 1. In his 1970 paper, Codd goes through the mathematics of relations
and
> > indicates that elements in relations could, themselves, be relations.
> > However, he suggests starting simply with relations that do not contain
> > relations.
> > 2. In the 1974 paper and in the normal form discussions, normal forms
are
> > described so that "n" normal form is data that is in 1st normal form and
> > then ...
> > 3. There is no mathematical foundation for putting the data into 1NF
> except
> > for what Codd and his followers indicate is that the model should be as
> > simple as possible but not simpler and they indicate that without
> resorting
> > to nested relations, the model is as simple as is needed. This is NOT a
> > mathematical conclusion.

>
>

Yes, but even as a hypothesis, it would not be a mathematical one. That is fine with me as I have many hypotheses that would require emperical data to be proven. However, it seems to me that a lot of students of relational database theory mistakenly think that there is some mathematical proof that shows us this is the way to go in how we store and query data. While there is a mathematical model involved, it is just one of many ways to model data and there is no mathematical proof that it is "right" and that any other is wrong. There is also, to my knowledge, no emperical data to suggest that it is "right" from the perspective of yielding overall better, faster, more reliable, etc software applications. So, I think there is a significant myth about relational theory that is written in many college database texts.

--dawn Received on Sun Feb 22 2004 - 01:43:58 CET