Abstract We consider how SQL-like query languages over object-relational schemata can be preserved in the setting of ontology based data access (OBDA), thus leveraging wide familiarity with relational technology. This is enabled by the adoption of the logic CFDI 8nc , a member of the CFD family of description logics (DLs). Of particular note is that this logic can fully simulate DL-LiteF core , a member of the DL-Lite family commonly used in the OBDA setting. Our main results present efficient algorithms that allow computation of certain answers with respect to CFDI 8nc knowledge bases, facilitating direct access to a pre-existing row-based relational encoding of the data without any need for mappings to triple-based representations.