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This is a semantic extension to Basic Graph Patterns that allows SPARQL queries to be sensitive to the semantics of OWL ontologies.

Feature description

People working with OWL ontologies want to be able to perform conjunctive queries over those ontologies. They may have started with RDF or RDFS and SPARQL/RDF but now have added some OWL axioms to further enrich their data. Ideally, their SPARQL queries should yield more results. Or they may be OWL ontologies who have been using custom query languages (like Racer's NRQL) and wish to port their application between reasoners.

With the new OWL Profiles, we can expect many more implementations that can and wish to provide conjunctive query over ever larger OWL knowledge bases.

Ideally, the same query against the same graph(s) will yield sensibly related results under "normal" BGP semantics as well as under OWL semantics.


e.g. sample Query highlighting necessary syntax extensions, expected output, or modified/extended result format, endpoint self description mock-up syntax, etc.

Existing Implementation(s)

Here is a dated list. Most of the reasoners support some form of conjunctive query, often with SPARQL syntax.

Existing Specification / Documentation

There is a paper.

See also email: 2009AprJun/0207 (same: thread view).


The intent is that any legal SPARQL/OWL query will, for consistent graph, return a superset of the answers gotten querying the graph under standard BGP semantics.

There are some issues surrounding BNodes.

Links to postponed Issues

Has this extension/use case some history in the group already? I.e. are there posponed issues or archived mail-threads related to this originating from DAWG?

Related Features

List and possibly link to other use cases or extensions that relate to that use case. That will help us grouping them together in the end.


  • Bijan Parsia, University of Manchester
  • Chime Ogbuji, Cleveland Clinic Foundation

Use cases

A description of one or more use cases, the solution of which requires this feature. Multiple use cases can be added to each feature.