Building the Data Warehouse

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Going from the Data Warehouse
to the Operational Environment_

The operational environment and the data warehouse environment are about as different as any two environments can be in terms of content, technology, usage, communities served, and a hundred other ways. The interface between the two environments is well documented. Data undergoes a fundamental transformation as it passes from the operational environment to the data warehouse environment. For a variety of reasons—the sequence in which business is conducted, the high performance needs of operational processing, the aging of data, the strong application orientation of operational processing, and so forth—the flow of data from the operational environment to the data warehouse environment is natural and normal. This normal flow of data is shown in Figure 3.45.

The question occasionally arises, is it possible for data to pass from the data warehouse environment to the operational environment? In other words, can data pass in a reverse direction from that normally experienced? From the standpoint of technology, the answer certainly is yes, such a passage of data is technologically possible. Although it is not normal, there are a few isolated circumstances in which data does indeed flow “backward.”

Figure 3.45 The normal flow of data in the legacy application/data warehouse architected environment.

Direct Access of Data Warehouse Data

Figure 3.46 illustrates the dynamics of the simplest of those circumstances-the direct access of data from the data warehouse by the operational environment. A request has been made within the operational environment for data that resides in the data warehouse. The request is transferred to the data warehouse environment, and the data is located and transferred to the operational environment. Apparently, from the standpoint of dynamics, the transfer could not be easier.

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