J. Huber, C. Hawel, E. Weippl, W. Essmayr. Integrating data warehouses versus building a federated data warehouse: A comparison. number SCCH-TR-0218, 2002.
- Johannes Huber
- Christian Hawel
- Edgar Weippl
- Wolfgang Essmayr
||The explosive take up of data warehouses and their penetration of commercial markets has put many businesses under pressure to integrate data warehouses with clients, suppliers or after mergers. There are two basic ways of addressing this issue: First, integrating existing DWHs into a new DWH. Second, linking data warehouses to form a federated system in which local DWHs continue to exist and can be administered autonomously. In this paper we compare the two approaches. Moreover, we highlight in which cases federated DWHs are useful and elaborate on the representation of the schemas as XML description. Additionally, we present how such a federation can be built using XML-based queries; mediators translate these queries for each DWH in the federation and the federated layer combines the results.