Building the Data Warehouse

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Setting the Stage for Reengineering

Although indirect, there is a very beneficial side effect of going from the production environment to the architected, data warehouse environment. Figure 1.15 shows the progression.

In Figure 1.15, a transformation is made in the production environment. The first effect is the removal of the bulk of data—mostly archival—from the production environment. The removal of massive volumes of data has a beneficial effect in various ways. The production environment is easer to:

■■ Correct ■■ Restructure ■■ Monitor ■■ Index

In short, the mere removal of a significant volume of data makes the production environment a much more malleable one.

Another important effect of the separation of the operational and the data warehouse environments is the removal of informational processing from the

data warehouse environment

production environment. Informational processing occurs in the form of reports, screens, extracts, and so forth. The very nature of information processing is constant change. Business conditions change, the organization changes, management changes, accounting practices change, and so on. Each of these changes has an effect on summary and informational processing. When informational processing is included in the production, legacy environment, maintenance seems to be eternal. But much of what is called maintenance in the production environment is actually informational processing going through the normal cycle of changes. By moving most informational processing off to the data warehouse, the maintenance burden in the production environment is greatly alleviated. Figure 1.16 shows the effect of removing volumes of data and informational processing from the production environment.

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