Semantic enrichment of interoperable databases

Integrated access to a federated database system, requires a deep knowledge about the semantics of its component databases so that interdatabase semantic relationships can be detected. Unfortunately, very often there is a lack of such a knowledge and the local schemas do not help to acquire it. The solution is to upgrade the semantic level of the local schemas through a semantic enrichment process where implicit knowledge is discovered and made explicit. The author outlines a methodology for semantic enrichment consisting of two phases. In the knowledge acquisition phase, restrictions in the form of different types of identifiers and dependencies of several kinds of are discovered by analyzing the intension and the extension of the database. Then, in the conversion phase, the schemas augmented with this knowledge are converted to rich schemas expressed in a canonical object oriented model