TABLE OF CONTENTS The demonstration will follow roughly the process indicated in Figure 7.6. In this figure, the dark-gray boxes indicate logical data objects, such as relations, queries, or materialized (possibly multi-dimensional) views. The light-gray boxes describe conceptual models. In DWQ, these are externally represented as extended Entity-Relationship models and are internally modeled using Description Logic formalisms from artificial intelligence to allow for subsumption reasoning. Steps 1 though 6 represent the extended design approach shown in the demonstration. The two ovals describe related support at the operational level, focusing on the two key problems of aggregate query optimization and view refreshment. The whole process is administered through a metadata repository that has been implemented using the Concept-Base system [ [15]].
In the following subsections, we briefly describe the main steps of the demonstration and point to literature where more details about the underlying theory or industrial applications can be found.
The DWQ approach to source integration is incremental: whenever a new portion of a source is taken into account, the new information is integrated with an "Enterprise Model", and the necessary new relationships are added. Thus, the Enterprise Model provides a consolidated view of the concepts and the relationships that are important to the enterprise and have been currently analyzed. Such a view is subject to changes and additions as the analysis of the information sources proceeds. The main concepts used in the DWQ approach are...
