The RDF SPARQL Endpoint module indexes the RDF data publicly available on a Drupal site into an ARC2 RDF store. It also provides a SPARQL endpoint via the ARC2 SPARQL interface.
Because it relies on the ARC2 library, this module requires MySQL and will not work on other databases. The SPARQL module should be used instead if another database support is required.
RDF SPARQL Endpoint requires the modules:
* RDF - http://drupal.org/project/rdf (with the ARC2 library installed)
* (recommended) RDF CCK - http://drupal.org/project/rdfcck
You need to make sure the RDF data is publicly available at node/*/rdf (check the permission 'access RDF data' for anonymous user).
Why another SPARQL module?
The original SPARQL module intends to work in pair with the RDF module for Drupal, and will support any database backend. However its SPARQL support is not as mature as the SPARQL support of the ARC2 library. The downside of ARC2 is that it is MySQL specific (for now at least).