Building the Data Warehouse

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key


foreign key foreign key




key


foreign key


shipment


history




sales


history



key



vendor


key


history


foreign key foreign key


parts


history



foreign key


customer


history


Figure 6.36 Foreign keys in the data warehouse environment.


and it often satisfies the different political needs of the organization. With this option each group doing development can feel that it has some degree of control of at least its own peculiar needs. Unfortunately, this option has several major drawbacks. First, multiple technologies must be purchased and supported. Second, the end user needs to be trained in different technologies. And finally, the boundaries between the technologies may not be as easy to cross. Figure 6.39 illustrates this dilemma.

data common to development groups A, B, C, D



platform B



data unique to development group B


data common to development groups A, B, C, D


common technological platform


Figure 6.37 The different types of data in the detailed level of the data warehouse all on a common platform.



platform C


Figure 6.38 In this case, the different parts of the detailed level of the data warehouse are scattered across different technological platforms.

Figure 6.39 Data transfer and multiple table queries present special technological problems.


If there are to be multiple technologies supporting the different levels of detail in the data warehouse, it will be necessary to cross the boundaries between the technologies frequently. Software that is designed to access data across different technological platforms is available. Some of the problems that remain are shown in Figure 6.40.

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