FedDW: A Tool for Querying Federations of Data Warehouses: Architecture, Use Case and Implementation

Recently, Federated Data Warehouses – collections of autonomous and heterogeneous Data Marts – have become increasingly attractive as they enable the exchange of business information across organization boundaries. The advantage of federated architectures is that users may access the global, mediated schema with OLAP applications, while the Data Marts need not be changed and retain full autonomy. Although the underlying concepts are mature, tool support for Federated DWs has been poor so far. This paper presents the prototype of the “FedDW” Query Tool that supports distributed query processing in federations of ROLAP Data Marts. It acts as middleware component that reformulates user queries according to semantic correspondences between the autonomous Data Marts. We explain FedDW’s architecture, demonstrate a use-case and explain our implementation. We regard our proof-of-concept prototype as a first step towards the development of industrial strength query tools for DW federations.

Keywords:Data Integration Systems, Heterogeneous Data Sources, Federated Data Warehouses, Distributed Query Processing, Software Engineering.