The RDF Data Access Working Group has published a Last Call Working Draft of the SPARQL Query Language for RDF. The working group invites all comments to the public-rdf-dawg-comments public mailing list until April 18.
The Working Group believes that this Last Call draft represents significant improvements to the SPARQL specification compared with previous versions. Excerpted from the recently published Last Call draft:
SPARQL can be used to express queries across diverse data sources, whether the data is stored natively as RDF or viewed as RDF via middleware. SPARQL contains capabilities for querying required and optional graph patterns along with their conjunctions and disjunctions. SPARQL also supports extensible value testing and constraining queries by source RDF graph. The results of SPARQL queries can be results sets or RDF graphs.
Compared to previous versions, this document adds an algebra for SPARQL that provides semantics for evaluating graph patterns and solution modifiers. This algebra is defined over basic graph pattern matching for simple entailment. This document also provides conditions for extending SPARQL basic graph pattern matching. This document also contains numerous editorial changes and bug fixes compared with previous versions.