Semantic Enrichment: A First Step to Provide Database Interoperability

Semantic enrichment is a process that upgrades the semantics of databases. Usually, this is done by remodelling database schemas in a higher data model in order to explicitly express semantics that is implicit in the data. We use the ODMG-93 standard for object-oriented database systems to this end. Hence relational database schemas are transformed into object-oriented ones, thereby making explicit relationships and subtype hierarchies. In contrast to other approaches, semantic enrichment must explicitly be speciied by means of rules that describe how object types and relationships between them are derived from relational tables. A powerful speciication language for such rules is proposed, which allows remodelling even complex relational situations in an intuitive and concise manner. Given any enrichment speciication, a complete database interface is generated, which provides an object-oriented access to relational data. Access methods are automatically implemented on top of the relational system.