Building the Data Warehouse

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The final level of data is the individual level. Individual data is usually temporary and small. Much heuristic analysis is done at the individual level. As a rule,


the individual levels of data are supported by the PC. Executive information systems (EIS) processing typically runs on the individual levels.


Data Integration in the Architected Environment


One important aspect of the architected environment that is not shown in Figure 1.11 is the integration of data that occurs across the architecture. As data passes from the operational environment to the data warehouse environment, it is integrated, as shown in Figure 1.12.


There is no point in bringing data over from the operational environment into the data warehouse environment without integrating it. If the data arrives at the data warehouse in an unintegrated state, it cannot be used to support a corporate view of data. And a corporate view of data is one of the essences of the architected environment.


In every environment the unintegrated operational data is complex and difficult to deal with. This is simply a fact of life. And the task of getting one’s hands dirty with the process of integration is never pleasant. In order to achieve the real benefits of a data warehouse, though, it is necessary to undergo this painful, complex, and time-consuming exercise. Extract/transform/load (ETL) software can automate much of this tedious process. In addition, this process of integration has to be done only once. But, in any case, it is mandatory that data flowing into the data warehouse be integrated, not merely tossed—whole cloth—into the data warehouse from the operational environment.

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