2. The method of claim 1 , further comprising, before step (a), searching for an ontology schema path between classes with respect to all classes stored in the ontology schema database, respectively, and storing the searched ontology schema paths in the ontology schema path database.
2. The method of claim 1 , further comprising, before step (a), searching for an ontology schema path between classes with respect to all classes stored in the ontology schema database, respectively, and storing the searched ontology schema paths in the ontology schema path database. 3. The method of claim 2 , further comprising, if an update of the ontology schema database is detected, searching for an ontology schema path of the updated class and updating the ontology schema path database.