- From: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
- Date: Mon, 19 Jul 2004 23:53:26 +0100
- To: "'RDF Data Access Working Group'" <public-rdf-dawg@w3.org>
On Mon, Jul 19, 2004 at 05:21:29PM -0500, Dan Connolly wrote: > Perhaps the objective is fuzzy enough so that the conflict isn't > clear, but all the concrete designs I have seen > (e.g. the BRQL SOURCE mechanism) involve the input to the QUERY > being more than just an RDF graph. I understand it to be (opionally) a set of RDF grpahs. I would like it if the intention is that servers that do not need/use source information can ignore it, eg. treat all triples as having a single source. > The spec doesn't yet explicitly say what the input to a query > is, but it seems to be more than just a graph: > > "The SOURCE clause added to a triple pattern causes the variable or > literal to match or bind the RDF graph which the statement came from, if > the server knows." > -- http://www.w3.org/2004/07/08-BRQL/ > $Revision: 1.14 $ of $Date: 2004/07/19 13:11:51 $ > > Does anybody have any test cases for SOURCE? I'm sure those would > make this crystal clear. Some trivial ones, BRQLised: Data a.rdf: :foo :a "a" :foo :b "b" b.rdf: :bar :a "a" SELECT ?s WHERE (?s ?p ?o) SOURCE <a.rdf> +-------+ | ?s | +-------+ | :foo | +-------+ SELECT ?s, ?src WHERE (?s ?p ?o) SOURCE ?src +-------+-------+ | ?s | ?src | +-------+-------+ | :foo | a.rdf | | :bar | b.rdf | +-------+-------+ CONSTRUCT * WHERE (?s ?p ?o) SOURCE <a.rdf> should return an RDF graph equivalent to the orignal asserted a.rdf I think. I dont have a real test for this, but it seems very useful so I included it anyway. +---------------+ | * | +---------------+ | :foo :a "a" | | :foo :b "b" | +---------------+ - Steve
Received on Monday, 19 July 2004 18:53:31 UTC