During the past years, the most of research works dealing with the object multiple representation and evolution propose to enrich the monolithic vision of the classical object approach in which an object belongs to one hierarchy class. In particular, the viewpoint concept receives recently a widespread attention. Its integration to a data model gives flexibility for the conventional object-oriented data model and allows one to improve the modelling power of objects. The viewpoint paradigm can be used as a means for object multiple descriptions and as a means to master the complexity of the current database systems permitting a distributed manner to develop them. The motivation of this paper is twofold: to define an object data model integrating viewpoints in databases and to present a federated database system integrating multiple sources following a local-as-extended-view approach.
展开▼
