1. A method for processing an ontological query for data from any of a plurality of different databases on a network coupled to a computer, comprising: loading a ontological data model that comprises a plurality of logical models based on data from the plurality of different databases; compiling the ontological query and optimizing the compiled ontological query according to join and combination rules based on the logical models and describing meta-properties of the data and meta-relationships based on the meta-properties between the data from the plurality of different databases; and processing logical operations on the compiled ontological query, wherein the data from the plurality of different databases defines a hierarchy of ontologies in parent-child relationship, wherein the hierarchy of ontologies includes: a first child ontology accessing data from a first of the plurality of different databases; a second child ontology accessing data from a second of the plurality of different databases; and a parent ontology; wherein the first and second child ontologies contribute to the parent ontology such that the parent ontology accesses data from both the first and second databases.