
SPARQLIFY.ORG
sparqlifyIs a scalable SPARQL-SQL rewriter whose development began in April 2011 in the course of the LinkedGeoData project. Support of the Sparqlification Mapping Language (SML), an intuitive language for expressing RDB-RDF mappings with only very little syntactic noise. R2RML will be supported soon. Sparqlify does not evaluate expressions in memory. All SPARQL filters end up in the corresponding SQL statement, giving the underlying RDBMS has maximum control over query planning. Order By is pushed into the SQL.
http://www.sparqlify.org/