Design and Development of a Tool for Integrating Heterogeneous Data Warehouses

In this paper we describe the design of a tool supporting the integration of independently developed data warehouses, a problem that arises in several common scenarios. The basic facility of the tool is a test of the validity of a matching between heterogeneous dimensions, according to a number of desirable properties. Two strategies are then provided to perform the actual integration. The first approach refers to a scenario of loosely coupled integration, in which we just need to identify the common information between sources and perform drill-across queries over them. The goal of the second approach is the derivation of a materialized view built by merging the sources, and refers to a scenario of tightly coupled integration in which queries are performed against the view. We illustrate architecture and functionality of the tool and the underlying techniques that implement the two integration strategies.