- From: Pat Hayes <phayes@ihmc.us>
- Date: Fri, 7 May 2004 13:50:09 -0500
- To: Kendall Clark <kendall@monkeyfist.com>
- Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
>Requirement >----------- >It should be possible to query the RDFS structure of an RDF graph to find, >for example, the parents and instances of a class or the class tree. > >Discussion >---------- >I'm not sure whether this comes down, in the end, to a semantic requirement >or just a request for sugar for a particular kind of query; but what my >users need (and we have implemented in a really ugly, API munging way) is >the ability to ask for all the instances of a class, Query: [??x rdf:type ex:TheClass .] (using ?? to flag a must-bind) should get you all the instances that are listed in the graph. Whether that is ALL instances is another matter altogether:I don't think that it makes sense to ask that as an RDF query. > all the parents ?Superclasses? If so, Query: [ex:TheClass rdfs:subClassOf ??x] should work, but what you get will certainly not be *all* of them. You might be unpleasantly surprised by how many of them there are, even if the set of all of them was computable. Pat >of a >class, and so on. Being able to do these queries, and being able to do them >"easily" (yes, I know, untestable, but still...) is a real requirement for us. > >The DIG Description Logic Interface ASK language is, more or less, what we'd >like to have. See <http://dl-web.man.ac.uk/dig/>. > >Best, >Kendall Clark -- --------------------------------------------------------------------- IHMC (850)434 8903 or (650)494 3973 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32501 (850)291 0667 cell phayes@ihmc.us http://www.ihmc.us/users/phayes
Received on Friday, 7 May 2004 14:50:11 UTC