- From: <jos.deroo@agfa.com>
- Date: Thu, 11 Nov 2004 15:56:08 +0100
- To: public-rdf-dawg@w3.org
making use of the excellent service at http://sparql.org/query.html I asked 1/ PREFIX dc: <http://purl.org/dc/elements/1.1/> PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> CONSTRUCT ($book rdf:type owl:Nothing) WHERE ($book dc:title $title) and got result graph @prefix dc: <http://purl.org/dc/elements/1.1/> . @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix owl: <http://www.w3.org/2002/07/owl#> . <http://example.org/book/book2> a owl:Nothing . <http://example.org/book/book4> a owl:Nothing . <http://example.org/book/book1> a owl:Nothing . <http://example.org/book/book5> a owl:Nothing . <http://example.org/book/book3> a owl:Nothing . which is inconsistent and that is because the query (when seen as rule) is inconsistent. 2/ PREFIX dc: <http://purl.org/dc/elements/1.1/> PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> CONSTRUCT ($book dc:title $test) WHERE ($book dc:title $title) and got empty result graph My implementation actually returns :Paper :authorName ?test. which is because we made it so to return substitution results (constructed as RDF graph) for unbound variables (e.g. in the case of OR or OPTIONAL) But I can understand the returning of the empty graph as it is according to my understanding that the proof result atoms should be in the Herbrand base of the query formula. (Herbrand Base is the set of all ground atoms that can be formed from predicate symbols from a clause in Skolemized form S and terms from the Herbrand universe H of S. Herbrand universe of S is the set of all closed terms constructed from the constant and function symbols of S) -- Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Thursday, 11 November 2004 14:56:45 UTC