Ziqi Zhang, I think the blank node ID needs treatment, because can change in each reading. Mostly if the IDs are not saved in the same database. But I not sure about what's happened (I'm curious).
2013/3/6 Ziqi Zhang <[email protected]> > Hi > > I may have misunderstood something but here is my problem. > > I am using Jena API to get triples from this SPARQL endpoint: > http://sparql.sindice.com/**sparql <http://sparql.sindice.com/sparql> > My query is: > -------------- > SELECT DISTINCT ?s ?o WHERE { > ?s rdf:type rdfs:Class . > {?s foaf:name "species"@en .} > UNION {?s foaf:name "species" .} > OPTIONAL {?s owl:equivalentClass ?o .} > } > -------------- > > The query should return 5 results, each about a *blank node*. If you send > the query using the web interface above, you should get the following > results: > --------------------------- > s o > nodeID://b122741495 http://purl.org/science/** > protein/bysequence/ncbi_gene.**42069<http://purl.org/science/protein/bysequence/ncbi_gene.42069> > nodeID://b122741495 http://purl.org/science/** > protein/bysequence/ncbi_gene.**42504<http://purl.org/science/protein/bysequence/ncbi_gene.42504> > nodeID://b122741495 http://purl.org/science/** > protein/bysequence/ncbi_gene.**47877<http://purl.org/science/protein/bysequence/ncbi_gene.47877> > nodeID://b122741495 http://purl.org/science/** > protein/bysequence/ncbi_gene.**42945<http://purl.org/science/protein/bysequence/ncbi_gene.42945> > nodeID://b122741495 nodeID://b122741495 > > > --------------------------- > > However, using Java Jena API and the following, code, I get completely > different blank node IDs: > ---------------------- > s o > 32ec7330:13d4066f80a:-7fff http://purl.org/science/** > protein/bysequence/ncbi_gene.**42069<http://purl.org/science/protein/bysequence/ncbi_gene.42069> > 32ec7330:13d4066f80a:-7fff http://purl.org/science/** > protein/bysequence/ncbi_gene.**42504<http://purl.org/science/protein/bysequence/ncbi_gene.42504> > 32ec7330:13d4066f80a:-7fff http://purl.org/science/** > protein/bysequence/ncbi_gene.**47877<http://purl.org/science/protein/bysequence/ncbi_gene.47877> > 32ec7330:13d4066f80a:-7fff http://purl.org/science/** > protein/bysequence/ncbi_gene.**42945<http://purl.org/science/protein/bysequence/ncbi_gene.42945> > ---------------------- > > Why are the IDs different? because they are different, I cannot do further > queries on the node at the sparql end point. What I mean is, if I then > query: > "Select ?p ?o where{32ec7330:13d4066f80a:-**7fff ?p ?o .}" > I will have no results, because the node ID does not match with > "nodeID://b122741495". > > > Would really appreciate any insight to this! > > -- > Ziqi Zhang > > -- Fabio Aiub Sperotto Mestrando em Modelagem Computacional about.me/fabiosperotto www.twitter.com/fabio_gk
