RE: Refining Optionals

> -----Original Message-----
> From: Seaborne, Andy []
> Sent: Monday, July 11, 2005 1:14 PM
> To: Geoff Chappell
> Cc: 'RDF Data Access Working Group'; 'Pat Hayes'
> Subject: Re: Refining Optionals
> > An unbound var in a solution can be substituted with any RDF-T and the
> > solution will still be valid. Do you agree with that?
> I agree for the style of solution that your approach is taking.  The
> alternative
> is something more prescriptive that only has substitutions in the solution
> that
> are needed to make the pattern match.  This is the contrast between the
> narrowing down approach and the constructional one.
> If we compare the two approaches, are there any queries that given
> different
> solutions?

Well, considering the goal of my approach is to ultimately generate
pattern(s) that are evaluated constructionally, it's hard for me to argue
that you can't make the two approaches equivalent :-)  Your approach
requires that you take the union of all solutions for all possible group
orders to eliminate order dependency (right?). Perhaps you could look at my
approach as one way to determine which of those orders you need to actually
evaluate (since as you've suggested you couldn't reasonably do them all in a
practical application)?



Received on Monday, 11 July 2005 18:51:07 UTC