Let us examine some of the key defining features of the data warehouse based on these definitions. What about the nature of the data in the data warehouse? How is this data different from the data in any operational system? Why does it have to be different? How is the data content in the data warehouse used?
In operational systems, we store data by individual applications. In the data sets for an order processing application, we keep the data for that particular application. These data sets provide the data for all the functions for entering orders, checking stock, verifying customer's credit, and assigning the order for shipment. But these data sets contain only the data that is needed for those functions relating to this particular application. We will have some data sets containing data about individual orders, customers, stock status, and detailed transactions, but all of these are structured around the processing of orders.
Similarly, for a banking institution, data sets for a consumer loans application contain data for that particular application. Data sets for other distinct applications of checking accounts and savings accounts relate to those specific applications. Again, in an insurance company, different data sets support individual applications such as automobile insurance, life insurance, and workers' compensation insurance.
In every industry, data sets are organized around individual applications to support those ...