Schema Integration in Object-oriented Databases Schema Integration in Object-oriented Databases

This report presents a formal approach to support schema integration in object-oriented databases. The basis of the approach is a synthetic subclass order, which is deened in terms of a weak subtype relation on underlying types of classes and a subfunc-tion relation on functional forms of methods. Classes are identiied using an equivalence relation induced by the subclass order and factorised using a join operator w.r.t. the subclass order. Class hierarchies are integrated by repeatedly identifying and factorising classes. The novelty of this report is that both attributes and methods are used to compare classes and behaviour of methods is used to compare attributes.