Data Warehousing Concepts

A data warehouse is a non-volatile copy of data that is usually also subject-oriented, time-variant, and integrated from multiple data sources.

• non-volatile: Once the data is in the warehouse it will not be modified or deleted
• subject-oriented: The data is usually designed to facilitate analysis and reporting for a particular subject area (eg: sales)
• time-variant:Historical data is stored, as opposed to just the latest relevant transaction
• integrated: Data from multiple sources is merged into the warehouse