Mediation in a Dynamic Context: Arguing for a Request-Oriented Approach and Structuring IT

Abstract

Approach by mediation to make multiple sources interoperable was essentially investigated when one known or when one can extract a priori the schema of each source. This approach is not appropriate for an opened and evolutionary context where sources are not identified a priori, where sources can evolve all the time, where requests of the users do not take place in a frame fixed in advance. It is a question of identifying sources and of discovering their properties in a automatic or partially automatic way while requests are formulated. We suggest in this chapter a request oriented approach which does not require a preliminary integration of the entire schemas of the sources. Only elements related to the request are detected, extracted and integrated. We explicit the different steps of such an approach and we discuss how existing techniques and recent research results can contribute to their feasibility. We characterize also remaining open problems.