Representing Functional Dependencies by the OWL Web Ontology Language

The OWL Web Ontology Language is developed for describing ontologies of Semantic Web. Since OWL is based on description logics, it can model schemata and their integrity constraints, and examine equivalence, consistency, redundancy, and satisfiability. However, it is not clear how much complex constraints on a database OWL can express. In this paper we discuss how functional dependencies of the relational model can be represented in OWL. We extend OWL with functional de- pendencies, and also discuss complexity of reasoning in the resulting OWL, called OWL fd . Encoding functional dependencies by OWL is useful for integrating heterogeneous schemata because we can examine integrity constraints and dependencies.