- From: Dave Reynolds <der@hplb.hpl.hp.com>
- Date: Wed, 03 May 2006 18:05:57 +0100
- To: Michael Kifer <kifer@cs.sunysb.edu>
- CC: public-rif-wg@w3.org
Michael Kifer wrote: >> Alex Kozlenkov wrote: >> >>> I am not sending a message against OWL or RDF. I am simply asking >>> whether _querying_ RDF and OWL in rule antecedents is enough or not for >>> RIF at this time. >> As I've already said in my response to the proposal, external-query-only >> is not sufficient from my point of view. I need to be able to express at >> least deduction rules over RDF and an external query approach doesn't >> facilitate that. I would prefer a tighter embedding of RDF into RIF >> (e.g. either a three place predicate or the ability to interpret any >> atoms over binary relations as RDF triple patterns). > > I think people have different ideas regarding what an "external query" > means - hence all this discussion (probably). > > For me, an external query means a predicate that represents some particular > aspects of an external system. This can have (and should have) several forms. > > For instance, if I just want to query RDF triples, OWL classes or roles, > then I should just be able to use 3-place/2-place/1-place predicates for > those things. E.g., motherOf(?X,?Y) to query the mother-of role in OWL. > > You can write your RDF or whatever rules over these predicates, and I think > this satisfies your requirements. Agreed. Although in the case of RDF deduction rules there is not necessarily any "external system" involved. > But I also may want to send a SPARQL query to an RDF base or to send a DL > expression to an OWL system. > For that we should have something like > > rdf_query('sparql stuff', list-of-variables-to-be-bound) > owl_query('some DL expr',...) Absolutely, I'm in no way denying the value of also being able to issue a SPARQL query including/especially one to an external data source. This is a good facility to have. Dave
Received on Wednesday, 3 May 2006 17:06:21 UTC