In This Chapter
Understanding what a data warehouse is and what it does
Looking at the history of data warehousing
Differentiating between bigger and better
Grasping the historical perspective of a data warehouse
Ensuring that your data warehouse isn't a data dump
If you gather 100 computer consultants experienced in data warehousing in a room and give them this single-question written quiz, "Define a data warehouse in 20 words or fewer," at least 95 of the consultants will turn in their paper with a one- or two-sentence definition that includes the terms subject-oriented, time-variant, and read-only. The other five consultants' replies will likely focus more on business than on technology and use a phrase such as "improve corporate decision-making through more timely access to information."
Forget all that. The following section gives you a no-nonsense definition guaranteed to be free of both technical and business-school jargon. Throughout the rest of the chapter, I assist you in better understanding data warehousing from its history and overall value to your business.
A data warehouse is a home for your high-value data, or data assets, that originates in other corporate applications, such as the one your company uses to fill customer orders for its products, or some data source external to your company, such as a public database that contains sales information gathered from all your competitors.