Abstract
Ontop is an Ontology Based Data Access system allowing users to access a relational database through a conceptual layer provided by an ontology. In this demo, we use the recently developed NPD benchmark (+4~billion triples) to demonstrate the features of Ontop. First we use Ontop as a SPARQL end-point to load the ontology and mappings, and answer SPARQL queries. Then, we will show how to use Ontop to check inconsistencies and exploit SWRL ontologies.