- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Tue, 22 Feb 2011 17:27:30 +0000
- To: SPARQL Working Group <public-rdf-dawg@w3.org>
Dataset-UNION is defined to do an RDF merge - it should be set-union. Graph store: DG: { _:a :q :r } INSERT { ?x :p 123 . } WHERE { ?x :q :r } then we get: _:a :q :r . _:x :p 123 . because bnodes are not equated in a merge, but are renamed apart: [[ http://www.w3.org/TR/rdf-mt/ if they do share blank nodes, then it is the union of a set of graphs that is obtained by replacing the graphs in the set by equivalent graphs that share no blank nodes. This is often described by saying that the blank nodes have been 'standardized apart'. ]] it needs to be a set union. Constant bnodes are treated by naming apart, for and every query solution, but not for bnodes arriving by variable substitution. Dataset(modify_template,P) can handle the renaming apart, the dataset-union can then be a union. Andy PS The link <http://www.w3.org/2009/sparql/docs/update-1.1/definition%20in%20rdf-mt> does not work.
Received on Tuesday, 22 February 2011 17:28:09 UTC