Data warehouse configuration

In the data warehousing approach to the in tegration of data from multiple information sources, selected information is extracted in advance and stored in a repository. A data warehouse (DW) can therefore be seen as a set of materialized views defined over the sources. When a query is posed, it is evaluated locally, using the materialized views, without accessing the original information sources. The applications using DWs require high query per formance. This requirement is in conflict with the need to maintain in the DW updated in formation. The DW7 configuration problem is the problem of selecting a set of views to materialize in the DW that answers all the emeries of interest while minimizing the total query evaluation and view maintenance cost. In this paper we provide a theoretical frame work for this problem in terms of the relational model. We develop a method for dealing with it by formulating it as a state space optimization problem and then solving it using an exhaustive incremental algorithm as well as a heuristic one. Wo extend this method by considering the case where auxiliary views are stored in the DW solely for reducing the view maintenance cost.