On-demand RDF to relational query translation in Samizdat RDF store

This paper presents an algorithm for on-demand translation of RDF queries that allows to map any relational data structure to RDF model, and to perform queries over a combination of mapped relational data and arbitrary RDF triples with a performance comparable to that of relational systems. Query capabilities implemented by the algorithm include optional and negative graph patterns, nested sub-patterns, and limited RDFS and OWL inference backed by database triggers.