Subrahmanian, et al. (1996) established a data source paradigm. There are two important aspects to constructing the data source paradigm: domain integration and semantic integration. Domain integration is the physical linking of data sources and systems, while semantic integration is the coherent extraction and combination of the information provided by the data and reasoning sources, to support a specific purpose (Subrahmanian, et al., 1996).

It is acknowledged that data warehousing is the most effective way to provide the business decision support data (Van Den Hoven, 1998). Under this concept, data is derived from operational systems and external information providers, and subsequently conditioned, integrated, and changed into a read-only database that is optimized for direct access by decision makers. The term ‘data warehousing' describes data as an enterprise asset that must be identified, cataloged, and stored to ensure that users will always be able to find the needed information. The data warehouse is generally enterprise-wide in scope, and its purpose is to provide a single, integrated view of the enterprise's data, spanning all enterprise activities (Van Den Hoven, 1998).

This paper identifies and compares the issues, methods, and results of efforts that involve integrating different data sources 1) within one organization, and 2) across multiple organizations.