Re: Syntacs, Semantics, and the Problem Domain

"dawn" <dawnwolthuis_at_gmail.com> wrote in message news:1142209572.359169.190150_at_u72g2000cwu.googlegroups.com...
>
> David Cressey wrote:

>
> Agreed. This has to do with the difference between a conceptual model
> of the data and an implementation (typically called logical) data
> model. The conceptual model should indicate whether something is a
> list or not. The logical/implementation model might be different
> depending on the target dbms, however.
>

The difference between "logical" and "physical" as often used in c.d.t. is not the same as the distinction as used in the texts that originally taught me relational databases. It is also not the same as the distinction between such things as "logical page numbers" and "physical page numbers" that I had dealt with in years prior to being exposed to relational databases.

Many people in c.d.t. use the term "logical" where I would have used the term "conceptual".

In this particular circumstance, I think your usage and mine are rather similar.

> > Now, most of the
> > problems I have with the comments of pickies generally in c.d.t. is
that,
> > nearly always, they come down to the idea that a team consisting of two
or
> > three pickies are so very productive that they can provide all the
technical
> > services to support and run a large scale database.
>
> I don't know if I'm in that group, nor do I recall when I've talked
> about how many people support large Pick systems.

You know what you've written better than I know what you've written. More importantly, you know whether you really meant it, or whether you were just pushing somebody's buttons.

I do recall someone other than you saying that the ratio of Pick programmers to SQL programmers, for the same result was something like ten to one. When the same person admitted later to not knowing anything about SQL, I dismissed that comment as the voice of ignorance and arrogance.

> I would claim
> (without proof) that, in general, if you have a system with similar
> features implemented in a SQL-DBMS and a Pick DBMS, you will need fewer
> developers/dbas supporting the Pick system. I have surely seen shops
> where there are more than two or three Pickies supporting the large
> scale system, however.
>
> > I don't think so. I remain unconvinced. And unless there is a FORMAL
> > vehicle for speading understanding about :what the data really means"
among
> > all stakeholders,
>
> I agree that the meaning of the data is of utmost importance. The
> ability to have synonyms in Pick is both an advantage in this as well
> as a way to junk up a system with too many words for the same thing.
>

The synonym problem and, worse yet, the homonym problem, is by not means pecusliar to Pick, or to RDM, or to any other particular system for the representation of data. It is inherent in the way people use symbols. The synonym problem and the homonym problem, together, make data analysis much more difficult.

And it brings into sharper focus than ever the need for a FORMAL vehicle for spreading understanding about "what the data really means". Received on Mon Mar 13 2006 - 23:43:33 CET