Ontology-based data access systems

Abstract

Studies aimed at ensuring semantic access to databases have a long history and originated at early stages of database technology development. Unfortunately, they have not led yet to the creation of widely accepted industrial technologies. In the last decade, the activity of the W3C consortium in the field of Semantic Web and development of standards of the ontology description languages induced a new activity wave in developing tools for systems of semantic access to databases and a new class of database systems, the so-called ontology-based data access (OBDA) systems. In such systems, ontology is used as a conceptual schema of the subject domain and as a basis of the user interface for SQL database systems. Approaches proposed in recent years do not ensure "final" solution of the problem. Nevertheless, ontology description languages were created that make it possible to achieve an acceptable compromise between their expressiveness, which remains sufficient for many applications, and computational complexity of reasoning on ontologies and processing queries to data stored in large databases. Prerequisites have been created for appearance of industrial technologies for development of systems of the above-specified class. In the paper, a survey of recent basic results and developments in this field is presented.