Building the Data Warehouse

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Merging the data is easy in some cases. But in the case of large amounts of data or in the case of data coming from multiple sources, the merger of data can be quite an operation.

Finally, the report is built.

How long does this process take for company A? How much does it cost? Depending on the information that is needed and depending on the size and state of the legacy systems environment, it may take a considerable amount of time and a high cost to get the information. The typical cost ranges from $25,000 to $1 million. The typical length of time to access data is anywhere from 1 to 12 months.

Now suppose that an company B has built a data warehouse. The typical cost here ranges from $500 to $10,000. The typical length of time to access data is one hour to a half day. We see that company B’s costs and time investment for retrieving information are much lower. The cost differential between company A and company B forms the basis of the cost justification for a data warehouse. Data warehousing greatly lowers the cost of information and accelerates the time required to get the information.

Cost of Building the Data Warehouse

The astute observer will ask, what about the cost of building the data warehouse? Figure 2.26 shows that in order to generate a single report for company B, it is still necessary to find, access, integrate, and merge the data. These are the same initial steps taken to build a single report for company A, so there are no real savings found in building a data warehouse. Actually, building a data warehouse to run one report is a costly waste of time and money.

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