Basically, the data warehouse is a common collection of business data. Instead, data is stored on different systems in different locations, in different formats, with different codes, with different ways to access it, that were built at different times. Only current data is available .
Most operational systems overwrite data as new data comes in.
For example, an account balance changes over time. This lack of historical data prohibits an understanding of critical business trends. The data warehouse solves this problem by integrating data from across the organization, converting unintelligible codes to common terms, organizing similar types of data together, incorporating historical data, and by including special applications for viewing and analyzing this information. In short, the data warehouse turns data into information. Technical Definition Technically, the data warehouse is a unified information management architecture to support information delivery and access by multiple types of information users.