Re-engineering Object-Oriented Database Schemata by Concept Analysis

In several situations a re-engineering of a given database schema is necessary, for instance, to improve the comprehensibility of the schema or to support a more efficient access to the data. Whereas there is a theory of normalization for relational database schemata, a corresponding approach for object-oriented databases does not exist so far. In this paper we present an approach to transform object-oriented class hierarchies into a "normalized" form. Starting with an extensional analysis which is needed to provide certain information about relationships between existing classes, we apply the framework of formal concept analysis to derive a "normalized" class hierarchy.