Building the Data Warehouse

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■    State transition diagram


■    HIPO chart


■    Pseudocode


There are many contexts and environments in which a process model is invalu-able—for instance, when building the data mart. However, because the process model is requirements-based, it is not suitable for the data warehouse. The process model assumes that a set of known processing requirements exists—a priori—before the details of the design are established. With processes, such an assumption can be made. But those assumptions do not hold for the data warehouse. Many development tools, such as CASE tools, have the same orientation and as such are not applicable to the data warehouse environment.


the corporate model, the operational model, and the data warehouse model



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data warehouse


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data warehouse


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process model


Figure 3.7 How the different types of models apply to the architected environment.

The Data Warehouse and Data Models


As shown in Figure 3.8, the data model is applicable to both the existing systems environment and the data warehouse environment. Here, an overall corporate data model has been constructed with no regard for a distinction between existing operational systems and the data warehouse. The corporate data model focuses on and represents only primitive data. To construct a separate existing data model, the beginning point is the corporate model, as shown. Performance factors are added into the corporate data model as the model is transported to the existing systems environment. All in all, very few changes are made to the corporate data model as it is used operationally.

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