Integrating Databases into the Semantic Web through an Ontology-Based Framework

To realize the Semantic Web, it will be necessary to make existing database content available for emerging Semantic Web applications, such as web agents and services, which use ontologies to formally define the semantics of their data. Our research in the design and implementation of an ontology-based system, OntoGrate, addresses the critical and challenging problem of supporting human experts in multiple domains to interactively integrate information that is heterogenous in both structure and semantics. Databases, knowledge bases, the World Wide Web, and the emerging Semantic Web are some of the resources for which scalable integration remains a challenge. To integrate databases into the Semantic Web, we use Semantic Web ontologies to incorporate database schemas. An expressive first order ontology language, Web-PDDL, is used to define the structure, semantics, and mappings of data resources. A powerful inference engine, OntoEngine, can be used for query answering and data translation. In this paper, besides introducing new ideas in the OntoGrate system, we will elaborate on two case studies for which our system works well.