Creating and Using Data Warehouses Overview

Organizations collect data in the normal course of business operations. The purpose of a data warehouse is to consolidate and organize this data so it can be analyzed and used to support business decisions. In many cases a data warehouse contains the living history of the organization.

Data warehouses usually contain historical data, often collected from a variety of disparate sources such as online transaction processing (OLTP) systems, legacy systems, text files, or spreadsheets. A data warehouse combines this data, cleanses it for accuracy and consistency, and organizes it for ease and efficiency of querying.

Some definitions of a data warehouse include several elements such as a data preparation area, the cleansing process, the database that holds the data warehouse data, and the tools that organize and present the data to client applications. Other definitions restrict the data warehouse to the database that contains the data warehouse data. In large data warehousing applications, data is often segmented into specialized components, called data marts, that address individual components of the organization. Some definitions consider data marts to be part of the data warehouse; other definitions consider them to be separate entities. The intended meaning of the term data warehouse is usually clear from the context in which it is used. The topics in this section generally use the broadest definition and address individual elements as components within the context of the data warehouse.

Data warehousing is an advanced and complex technology. A complete treatment of data warehousing is not possible in this document, but many excellent books and training courses are available to enhance your understanding. The topics in this section discuss the elements and processes of data warehousing and identify the many powerful tools provided by Microsoft® SQL Server™ 2000 to help you in the task of creating, using, and maintaining a data warehouse.