Queries, the Missing Link in Automatic Data Integration

Abstract. This paper introduces the ontology mapping approach of a system that automatically integrates data sources into an ontology-based data integration system (OBDI). In addition to the target and source ontologies, the mapping al-gorithm requires a SPARQL query to determine the ontology mapping. Further, the mapping algorithm is dynamic: running each time a query is processed and producing only a partial mapping sufficient to reformulate the query. This approach enables the mapping algorithm to exploit query semantics to cor-rectly choose among ontology mappings that are indistinguishable when only the ontologies are considered. Also, the mapping associates paths with paths, instead of entities with entities. This approach simplifies query reformulation. The sys-tem achieves favorable results when compared to the algorithms developed for Clio, the best automated relational data integration system. We have developed an Ontology-based Data Integration (OBDI) system that departs from the conventional OBDI organization. The goal is to include automatic integration of new data sources, provided those data sources publish a self-describing ontology.