- From: Alberto Reggiori <alberto@asemantics.com>
- Date: Wed, 2 Feb 2005 12:22:32 +0100
- To: RDF Data Access Working Group <public-rdf-dawg@w3.org>
hi all, I have small question about an example I came up to test grouping Given the following data: <http://example.org/book/book1> <http://purl.org/dc/elements/1.1/title> "SPARQL Tutorial" . <http://example.org/book/book1> <http://example.org/ns#price> "42"^^<http://www.w3.org/2001/XMLSchema#integer> . <http://example.org/book/book2> <http://purl.org/dc/elements/1.1/title> "The Semantic Web" . <http://example.org/book/book2> <http://example.org/ns#price> "23"^^<http://www.w3.org/2001/XMLSchema#integer> . is the following query PREFIX dc: <http://purl.org/dc/elements/1.1/> PREFIX ns: <http://example.org/ns#> SELECT ?title ?price WHERE { ( ?x dc:title ?title ) ( ?x ns:price ?price ) } AND ( ( ?price < 30 ) || ( ?price > 40 ) ) going to fail accordingly to what stated in http://www.w3.org/2001/sw/DataAccess/rq23/#CombiningPatterns ? I think so - due the above query has two graph-patterns, and that the constraints by definition do not bind any var - it should fail While the following query would succeed PREFIX dc: <http://purl.org/dc/elements/1.1/> PREFIX ns: <http://example.org/ns#> SELECT ?title ?price WHERE ( ?x ns:price ?price ) { ( ?x dc:title ?title ) } AND ( ( ?price < 30 ) || ( ?price > 40 ) ) due that the first (top most) graph-pattern binds ?x and ?price accordingly In other words, in the implementation, while processing the blocks stack one should execute any "binding graph-pattern" first or fail if not possible. is this the correct behavior? thanks Alberto - Alberto Reggiori, @Semantics S.R.L. www.asemantics.com
Received on Wednesday, 2 February 2005 11:22:38 UTC