1. A data query system comprising: a first storage medium including a data schema having a data schema query language associated therewith; a second storage medium including an ontology model including classes and properties, the ontology model having an ontology query language associated therewith, wherein constructs of the data schema are mapped to corresponding classes, properties or compositions of properties of the ontology model; and an ontology query processor generating a query expressed in the data schema query language corresponding to a specified query expressed in the ontology query language, providing an additional data schema having an additional data schema query language associated therewith, wherein constructs of the additional data schema are also mapped to corresponding classes, properties or compositions of properties of the ontology model, and generating a query expressed in the additional data schema query language corresponding to the query expressed in the ontology query language.