Building the Data Warehouse

Chapter 9. Migration to the Architected Environment

Any architecture that must be implemented all at once, in a big bang, is doomed to failure in today's world. There simply is too much risk and too long a period to wait until there is a payback. In addition, trying to freeze changes to consider any path that is revolutionary (rather than evolutionary) is unrealistic.

It is very good news indeed that migrating to the architected data warehouse environment is a step-by-step activity that is accomplished one finite deliverable at a time. The most successful implementations of the architected environment have been those in which the data warehouse has been built one iteration at a time. In doing so, the data warehouse can be built for a minimum of employee resources and with absolutely minimal disruption to the existing applications environment. Both the size and the speed of iterative development are important. Results must be delivered quickly.

In this chapter, a generic migration plan and a methodology for development are discussed. The migration plan has been successfully followed by a wide number of companies; it is anything but a fanciful flight. The approach has been gleaned from the experiences of a number of companies. Of course, each company will have its own diversions and permutations. But the migration plan and approach have met with enough success in enough diverse companies to merit the confidence of the general-purpose developer.

A Migration Plan

The beginning point for ...