AN OBJECT-ORIENTED INTEGRATION FRAMEWORK FOR BUILDING HETEROGENEOUS DATABASE-SYSTEMS

The construction of Heterogeneous Database Systems (HDBS) is supported by the ZOO(IFI)1 system by making extensive use of object-oriented concepts. We adopt the so-called framework concept from object-oriented programming to provide an integration framework that incorporates the entire design and major parts of the software necessary to establish a homogenization layer on top of autonomous local database systems in the form of cooperating, reusable classes. The amount and complexity of the specific software necessary to plug a new component system into the HDBS is reduced considerably as it ''just'' requires to override predefined abstract methods in appropriate subclasses. As the interface (global data model) of the homogenization layer, an object-oriented data model is used that in particular provides support for complex objects. Additionally, it allows to flexibly and accurately specify the global usability of data stored in a local system.