Quad support for Sesame 2.x
We've recently added quad support to bigdata and integrated that support with Sesame 2.x. There are now three major database modes for RDF data: plain triples, plain triples with provenance (statement identifiers), and quads. Inference is not supported yet for quads. We plan to introduce query time inference support instead of eager closure.
[2] https://sourceforge.net/apps/trac/bigdata/roadmap
posted by Bryan Thompson at
10:20 AM
2 Comments:
Just curious, is provenance supported with the quads model as well?
Ryan, the bigdata provenance mode associates a unique internal identifier with each distrint (S,P,O) triple. For interchange and high-level query, that internal identifier looks like a blank node. This makes it possible to write simple queries which recover statements about statements using SPARQL. There is an example on our GettingStarted page[1]. There are several advantages to this approach, including that it only uses 1/2 of the footprint on the disk of a quad store.
We have not implemented statement identifiers for quads for two reasons. First, quads can be used to support a variety of provenance models. Second, there is not a readily available means to bind the quint position (the statement identifier) in SPARQL, which would drastically limit the utility of the quint position.
[1] https://sourceforge.net/apps/mediawiki/bigdata/index.php?title=GettingStarted
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