- From: RDB2RDF Working Group Issue Tracker <sysbot+tracker@w3.org>
- Date: Tue, 31 May 2011 15:54:05 +0000
- To: public-rdb2rdf-wg@w3.org
ISSUE-44 (duplicate quads): Duplicate quads generated by TriplesMaps [R2RML] http://www.w3.org/2001/sw/rdb2rdf/track/issues/44 Raised by: David McNeil On product: R2RML As far as I can see the R2RML spec does not describe the proper behavior in the case where TriplesMaps produce identical quads. I think a couple of sentences should be added to the spec to specifically say what should happen in this case. My understanding of the correct behavior is: * R2RML maps are to produce SPARQL RDF datasets. * SPARQL RDF datasets contain a collection of RDF graphs (many named and one default). * RDF graphs are sets of triples. * As "sets", RDF graphs do not contain duplicate triples. * Therefore SPARQL RDF datasets do not contain duplicate quads. * Therefore R2RML maps should not produce duplicate quads. In particular looking forward to SPARQL 1.1 aggregates I believe this is important to specify. Note, SPARQL queries run against the quads produced by an R2RML map can produce duplicate tuples.
Received on Tuesday, 31 May 2011 15:54:07 UTC