Re: Stored fields ordered left to right

"Jerome H. Gitomer" <jgitomer_at_erols.com> wrote in message news:3ffecf81$0$6735$61fed72c_at_news.rcn.com...
> Dawn M. Wolthuis wrote:
<snip>
> > In Codd's definition of a relation, however, he removes the ordering
> > requirement (by using names instead of positions) so that a "Codd
relation"
> > is a set of unordered tuples. Therefore, relational database theorists
> > often think that relations MUST be unordered, when in fact it is they
who
> > opted not to use the correct mathematical definition of the term.
> >
> > My point in stating this is that I'm writing up responses to a set of
> > questions that Chris Date put out regarding the MultiValue model and he
> > claims that MultiValue must not be relational (and I'll admit it isn't
by
> > his definition) because it has ordered tuples. That argument always
just
> > sounds out-n-out wrong to me since mathematical relations are ordered
> > tuples, dag nab it! So, I just had to clear this little matter up.
> >
<snip>
> >
> From the perspective of an assembly language software developer
> (a rapidly disappearing breed) Codd's use of names rather than
> positions is immaterial. This is because in assembly language
> development it is common practice to assign names as aliases to
> locations rather than use the location itself as an identifier.
> This practice came about because it was easer to remember
> meaningful names, e.g. Salary, that it was to remember memory
> locations, e.g. 0357321. Codd did nothing more than follow
> common practice by assuming the use of names as aliases for
> positions and the fact that he did so should not be taken to
> mean that he removed the ordering requirement.
>

Thanks for adding such insight. I absolutely agree with everything you said until the last few words. While I agree that whether a tuple is ordered with locations or "ordered" with names is immaterial, Codd's followers seem to be really invested in this "unordered tuple" thing. So, I was pointing out that models using ordered tuples are actually, really, mathematical relations.
Cheers! --dawn Received on Fri Jan 09 2004 - 17:16:58 CET