Re: A new proof of the superiority of set oriented approaches: numerical/time serie linear interpolation

"Jon Heggland" <jon.heggland_at_idi.ntnu.no> wrote in message news:f1ccmq$fni$1_at_orkan.itea.ntnu.no...
> paul c wrote:
> > Jon Heggland wrote:
> >> I think this is oversimplifying. Constraints are associated with
> >> variables, so we need the variables for something more than value
> >> aliases.
> >> ...
> >
> > Hadn't thought of that, perhaps it is so, I'm not sure yet. Still
> > thinking of a constraint as an expression that produces a value from one
> > or more others.
>
> A constraint is a boolean-valued expression, yes. But expressed in terms
> of variables---otherwise it would be a proposition, and not all that
useful.
>
> I don't think we disagree all that much. But the concept of "variable"
> is very simple, and very familiar. I think your talk about language
> devices and relations having one value is confusing rather than
> clarifying. Consider this:
>

The concept of "variable" is very simple from a process centric point of view. Since most of us were programmers before becoming database exprerts, the process centric point of view is thoroughly ingrained in us. I suggest that, from a data centric point of view, the concept of "variable" is a lot less simple than you and I tend to think it is.

> 'Integer variables are nothing more a language device, for talking about
> integers, whether the language is Java or English. They merely serve to
> save us specifying an integer everytime we refer to it.

Not exactly. In a programming language, it also serves to convey a computed result from one point of execution to a different point. Received on Thu May 03 2007 - 13:09:45 CEST