[Mulgara-dev] ITQL

[Life is hard, and then you die]

On Sat, Jul 12, 2008 at 08:43:11AM -0500, Paul Gearon wrote:
> On Sat, Jul 12, 2008 at 8:15 AM, David Wood <dwood at softwarememetics.com> wrote:
> > The W3C is starting to think about SPARQL+ (again).  I will be
> > reviewing the eventual contents of the org.mulgara.client.tql package
> > for fodder :)
[snip]
> Don't go copying trans(...) or walk(...).  I've never liked this
> syntax (I invented it) and I now have something better. Andrae's query
> transformation code now makes it possible to use the following instead
> of trans(...):
>   $x ns:ancestorOf $y .
>   ns:ancestorOf rdf:type mulgara:TransitivePredicate

Hmm, let me see if I fully understand this. Given the tql

  trans($x <rdf:next> <foo:bar> and $x <rdf:next> $y)

you suggest in sparql to express this as

  $x rdf:next foo:bar .
  $x rdf:next $y .
  rdf:next rdf:type mulgara:TransitivePredicate

> I like this, since it looks just like using owl:TransitivePredicate,
> only it refers to extrinsic statements instead. It also means we don't
> have to extend SPARQL to extend the functionality of our
> implementation. We just define certain predicates to refer to
> extrinsic statements.

Maybe I've misunderstood, but semantically this feels weird: I add a
constraint and as a result get _more_ results back?


  Cheers,

  Ronald