Integration of Heterogeneous Data Sources with Limited Capabilities in the Object-Oriented Mediator Engine AMOS II

Information becomes a more and more valuable asset in today’s organizations. Therefore the need of creating an integrated view over all available data sources arises. Several technical problems must be overcome in the design and implementation of a system for integrating different data sources. To the main obstacles count autonomy, data heterogeneity and different query capabilities of the repositories. This thesis presents the data integration system AMOS II , which is based on the wrapper-mediator approach. The main focus of this work lies on data model transformation and query processing. The following extensions to the AMOS II system are described in this thesis: • A framework for transforming various data models into the objectoriented model of AMOS II is presented. • The roles and tasks of wrappers are described. In particular their participation in query processing and query optimization is discussed. • A way for describing and utilizing the query capabilities of the different data sources is proposed. • Two different approaches to query processing over external data sources are developed and analyzed. All the proposed techniques are implemented in the AMOS II system, which runs on a Windows NT platform.