Data Integration ...

Data integration involves combining data residing in different sources and providing users with a unified view of these data. This process becomes significant in a variety of situations both commercial (when two similar companies need to merge their databases) and scientific (combining research results from different bioinformatics repositories, for example). Data integration appears with increasing frequency as the volume and the need to share existing data explodes. It has become the focus of extensive theoretical work, and numerous open problems remain unsolved. In management circles, people frequently refer to data integration as "Enterprise Information Integration" (EII). Data Integration is fundamental to data warehousing and is a vital process for a rich and robust data resource to deliver business intelligence solutions. Integration includes all of the activities necessary to acquire data from sources, and to transform and cleanse the data.

One approach to solve the data integration problem would be to extract the data out various database systems to one queriable schema. Architecturally, this offers a tightly coupled approach because the data reside together in a single repository at query-time.

References:

http://communication.howstuffworks.com/data-integration.htm

http://en.wikipedia.org/wiki/Data_integration

http://www-01.ibm.com/software/data/cognos/data-integration.html

http://msdn.microsoft.com/en-us/library/ms978572.aspx

http://www.tdwi.org/Certification/CBIP/display.aspx?id=7153