Re: What exactly are "Constraint programming" & "constraint databases" about ?

On Tuesday, January 12, 2016 at 11:09:18 AM UTC-8, Nicola wrote:
> On 2015-12-31 10:09:10 +0000, Erwin said:
>
> >>
> >>
> >> Since it seems that Springer has given free access to its books up to 2004,
> >> if you are interested you may download this:
> >>
> >> http://link.springer.com/book/10.1007/978-3-662-04031-7
> >>
> >> Nicola
> >>
> >>
> >
> > Thanks, but, well :
> >
> > (a) that link doesn't seem to immediately give me "free download" (of
> > the table of contents, yeah) and the "look inside" gives me access to
> > only two initial pages of each chapter.
> > (b) I was looking for a bit of introductory stuff that starts off with
> > a good answer, in layman's lingo, to the questions such as "why should
> > I even care" (*) (not with "we define a vocabulary as three sets F,P
> > and M").
> >
> > (*) question also known as, a.o. :
> > - what does it do that other databases cannot do ?
> > - what problem of mine do they intend to solve (or facilitate solving) ?
> > - why are they being researched ?
>
> Have you tried browsing the book on Google Books? §1.4-§1.7 (which you
> should be able to access almost entirely) do a good job, I think,
> explaining what it is all about.

There is also "Introduction to Constraint Databases" by P Revesz which seems quite accessible. Here is a query from that textbook:

(SELECT X, Y

               FROM        Town
               WHERE     Name = "Lincoln")
                     INTERSECT 
               (SELECT     X, Y
               FROM        Broadcast)

I have few problems with this query. It doesn't seem to be realistic: why would one enter constraints for broadcasting areas where elevation map and broadcasting signal function would suffice? Next question, how do people represent map data, I bet it is not a set of constraints... Can you exhibit an example where map data represented with constraints gives an advantage? Received on Tue Jan 12 2016 - 23:48:45 CET