RWTH Aachen University
There are many Query Languages (QLs) that can be used to query RDF (Resource Description Framework) and OWL (Ontology Web Language) ontologies but neither type is satisfactory for querying OWL-DL ontologies. RDF-based QLs (RDQL, SeRQL, SPARQL) are harder to give a semantics w.r.t. OWL-DL and are more powerful than what OWL-DL reasoners can provide. DL-based QLs (DIG ask queries, nRQL) have clear semantics but are not powerful enough in the general case. In this paper, the authors describe SPARQL-DL, a substantial subset of SPARQL for which they provide a clear OWL-DL based semantics.