Аннотация:The paper1 argues against cultivation in the ontological community of the opinion that ontologies are at the "semantic" level, whereas database schema are models of data at the "logical" or "physical" level. The paper claims that rather it would be right to consider OWL as yet another data model to be integrated with other heterogeneous information models. Applying the SYNTHESIS - an extensible language for heterogeneous information resource integration and mediator definition - we show how a sound mapping of a conceptual schemas expressed in OWL 2 QL into SYNTHESIS schemas can be defined. The soundness of the mapping is justified. The paper shows also how the integration of the OWL-defined databases into a SYNTHESIS-based mediator can be provided.