Originally published September 9, 2004
One of the great appeals of the data warehousing concept is that with a properly installed warehouse, there is a single version of the truth. There are many reasons why a single version of the truth is so appealing:
The appeal of the single version of the truth is valid and strong. It is a worthy goal for organizations everywhere.
But, does the notion that there should be a single version of the truth mean that there should be one physical data warehouse? In a large organization, there may be many physical renditions of data without violating the concept of the single version of the truth.
Take a large, complex multi-national organization such as IBM. There are simply too many products, product types and customers spread over different geographical areas and time zones in order for there to be a single data warehouse. One imagines that a successful company such as IBM would have different data warehouses for:
There simply is too much data to imagine that IBM would have a single data warehouse. And this principle applies not just to IBM but to every large complex organization.
If there are legitimate installations of physically separate data warehouses all residing within the concept of a single system of record, what then are the “rules of the road” for this phenomenon? Some of these are:
There are a surprisingly small set of rules for creating an environment of data integrity across a large and complex environment. Implementation of these rules, however, requires organizational discipline and the attitude of all organizational units working in harmony with other organizational units, which is easier said than done.
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