Building the Data Warehouse W. H. Inmon - Страница 285 из 402

One approach—which is on a track independent of the migration to the data warehouse environment—is to use the data model as a guideline and make a case to management that major changes need to be made to the operational

data model

data mart departmental/ individual systems

programs

Figure 9.5 The first major path to be followed is DSS.

data model

• organizational upheaval

• drastically changed requirements

Figure 9.6 To be successful, the data architect should wait for agents of change to

become compelling and ally the efforts toward the architected environment with the appropriate agents.

environment. The industry track record of this approach is dismal. The amount of effort, the amount of resources, and the disruption to the end user in undertaking a massive rewrite and restructuring of operational data and systems is such that management seldom supports such an effort with the needed level of commitment and resources.

A better ploy is to coordinate the effort to rebuild operational systems with what are termed the “agents of change”:

■■ The aging of systems ■■ The radical changing of technology ■■ Organizational upheaval ■■ Massive business changes

When management faces the effects of the agents of change, there is no question that changes will have to be made—the only question is how soon and at what expense. The data architect allies the agents of change with the notion of an architecture and presents management with an irresistible argument for the purpose of restructuring operational processing.

The steps the data architect takes to restructure the operational environment— which is an activity independent of the building of the data warehouse—are shown in Figure 9.7.

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