- From: Ian Davis <ian.davis@talis.com>
- Date: Fri, 14 Oct 2011 11:57:43 +0100
- To: William Waites <wwaites@tardis.ed.ac.uk>
- Cc: public-rdf-wg@w3.org
- Message-ID: <CAAiX05GP-yUpZJteTaCFJGbuSiLa4aWuU6E6uWhidrUiccr2kg@mail.gmail.com>
On Fri, Oct 14, 2011 at 11:45 AM, William Waites <wwaites@tardis.ed.ac.uk>wrote: > On Fri, 14 Oct 2011 10:45:34 +0100, Ian Davis <ian.davis@talis.com> said: > > iand> Example Document 3 in the TriG spec[1] shows the same blank > iand> node label being used in different graphs. My interpretation > iand> of the example is that those blank nodes are distinct, > iand> i.e. the scope of blank node labels is the graph not the > iand> TriG document. How do the main graph stores behave? Is it > iand> possible to put the same blank node into two different > iand> graphs? If so, this information would not be serializable in > iand> TriG if my interpretation is correct. > > I agree with your interpretation. However 4store appears to have > different behaviour here: > > @prefix ex: <http://example.org/>. > > ex:g1 { > _:s a ex:T > } > > ex:g2 { > _:s a ex:T > } > > And this query: > > SELECT * WHERE { > { GRAPH <http://example.org/g1> { ?s ?p ?o } } UNION > { GRAPH <http://example.org/g2> { ?s ?p ?o } } > } > > Shows the bnodes as having been merged when you run it here: > > http://gallows.inf.ed.ac.uk/data/test/ > > (note, I converted the TriG document to N-Quads to import it but I > don't think that should matter) > > I think it does matter. What was the N-Quads document that was thew result of the conversion. For comparison I loaded the following quads into Jena/TDB _:bnode <http://example.com/p> "foo" <http://example.com/g1> . _:bnode <http://example.com/p> "bar" <http://example.com/g2> . And get merged results from the query "describe ?s where { graph ?g {?s ?p ?o}}" [] <http://example.com/p> "foo" ; <http://example.com/p> "bar" . Ian -- Ian Davis, Chief Technology Officer, Talis Group Ltd. http://www.talis.com/ | Registered in England and Wales as 5382297
Received on Friday, 14 October 2011 10:58:22 UTC