<P> Regarding data integration, Rainer states, "It is necessary to extract data from source systems, transform them, and load them into a data mart or warehouse". </P> <P> Rainer discusses storing data in an organization's data warehouse or data marts . </P> <P> Metadata are data about data . "IT personnel need information about data sources; database, table, and column names; refresh schedules; and data usage measures". </P> <P> Today, the most successful companies are those that can respond quickly and flexibly to market changes and opportunities . A key to this response is the effective and efficient use of data and information by analysts and managers . A "data warehouse" is a repository of historical data that are organized by subject to support decision makers in the organization . Once data are stored in a data mart or warehouse, they can be accessed . </P>

Explain the components of data warehouse in detail