DBOWL is a persistent and scalable OWL reasoner. Ontologies are stored in a relational database, using a description logic reasoner to pre-compute the class and property hierarchies and to obtain all the ontology information (i.e. properties domain and range) which is also stored in the database. Furthermore, a simple but expressive query language has been implemented, which allows us to query and reason on these ontologies. Currently, we are implementing a SPARQL query engine for DBOWL.