A framework for object integration in the context of a multidatabase environment.

摘要

Traditional solutions to distributed heterogeneous database systems mainly focus on resolving the schematic and semantic incompatibility among the local databases to support interoperability. However, the limitations of such approaches are evident in many dynamic-application domains where changes might occur frequently. In particular, it is impractical to assume that in such environments, the global system would remain valid and frozen in time once it is in place. Since a distributed heterogeneous database system maintains many disparate databases to support such applications, efficient support for the ability of distributed objects to evolve is not only important but critical.; In view of the above, the objective of this thesis is to study, analyze, and define a framework that describes the dynamic characteristics of active objects in distributed databases. In particular, we characterize the underlying foundations of the ability of object to evolve in a multidatabase context and clarify the temporal semantics of active objects. These abstract concepts are mapped in a simple model. The model expressively represents temporal changes, conditions, and events in the real world. Based on the model, we design an architectural framework that incorporates event-driven production rules to automatically react to anticipated changes of local databases and global users and to dynamically reconfigure the global interfaces, so as to support interoperability over time. For validation and simulation of our work, a prototype is developed and built on top of CORBA's architecture.