Re: database systems and organizational intelligence

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"Dawn M. Wolthuis" <dwolt_at_tincat-group.com> wrote in message news:c94eft$sfl$1_at_news.netins.net...
> "Alan" <not.me_at_uhuh.rcn.com> wrote in message
> news:gvdtc.22728$4%3.3430_at_nwrdny01.gnilink.net...
> > Top-posting - please don't shoot me.
> >
> > The definitions, examples, and explanations I've given of functional
> > dependency are either quoted directly or paraphrased slightly from
> > "Fundamentals of Database Systems" 3rd Ed. by Elmasri & Navathe. This
> text
> > is used in Masters programs at major universities.
>
> I haven't read this book (do you recommend it?), but from this text you
are
> able to determine that functional dependencies have nothing to do with
> functions?
>
> > GPA as you have described is an example of "derived" data. It is based
on
> > data already stored. Of course code and functions (which are just
> > pre-written chunks of code)
>
> Functions can be specified with code. A function is, by definition, a
> relation. I wouldn't call any relation, including a function a chunk of
> code, but there is the specification (formula) for the function, which is
> encoded in some way.

I have heard many times that functions are a particular kind of relations. But the term function has a nuance of action and the term relation has a nuance of stability.

> > are needed to extract data, but that does not
> > mean that code and data are the same thing. You are essentially saying
> that
> > driving a car and directions to a destination are the same thing.
> Directions
> > are data (information, actually), driving is code (specific actions
taken
> to
> > affect a certain result). They are two different things.
>
> In that case, source code is data and object code that is "running" is
code,
> right? What about data that is fed as input to code to alter the course
> (e.g. parameters)? Is it data as coded (source code) and then code when
> applied during execution or does it remain data throughout? If source
code
> is executed by an interpreter instead of a compiler, then does it switch
> from being instructions (data) to code when the interpreter is taking it
in
> as parameters? I don't think you have hit the nail on the head with this
> distinction of directions vs. driving, but I could be wrong (it's happened
> before).

I'd suggest that code is the driving code not the specific actions.

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