Building the Data Warehouse

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development group A

OLAP


development group C


Figure 6.28 The development organization that is developing the lowest level of detail is the organization that uses the data model.


development group B


levels of summarization will require much less data, especially at the higher levels of summarization. It is overkill (and expensive) to place the higher levels of summarized data on the same platform as the detailed data (although it can be done).


Another reason is that the alternative platforms offer a wide variety of specialized software, much of which is not to be found on the monolithic platforms that house detailed data. In any case, whether the different levels of data are on a single platform or on multiple platforms, meta data must be carefully stored and managed, so that continuity from one level of detail to the next can be maintained.


Because different platforms are commonly used for the different levels of data that are being developed by different groups, the issue of interconnectivity arises. Figure 6.29 shows the need for interconnectivity from one level to the next.


Several aspects of interconnectivity need to be addressed. One issue is the compatibility of access at the call level. In other words, is there compatible syntax between the two technologies that make up the detailed and the summary data between any two levels of the warehouse? If there is not at least some degree of compatibility, the interface will not be usable. Another aspect of the interconnectivity issue is the effective bandwidth of the interface. If very heavy traffic is being created by processing that occurs on either level of the data warehouse, the interface between the two environments can become a bottleneck.

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