摘要：The goal of the paper is to define conditions, under which semantics of OWL 2 ontologies may be preserved in relational database, and to demonstrate that the hybrid approach for transforming OWL 2 ontologies into relational databases possesses such capability. The paper analyzes requirements for ontologies under transformation as ontology normalization and integrity rules, and presents an example model of Vehicle ontology, conforming to these rules. A schema of a database generated by applying the hybrid approach maps part of ontology concepts to relational database concepts on the base of their common semantics; ontology constructs having no direct equivalents in databases are stored in metatables. SQL queries are presented that demonstrate how metatables may be used for extracting rich information covering semantics of source ontology.
