A data warehouse is a relational database that is designed for query and analysis rather than for transaction processing. It usually contains historical data derived from transaction data, but can include data from other sources. Data warehouses separate analysis workload from transaction workload and enable an organization to consolidate data from several sources.
In addition to a relational database, a data warehouse environment can include an extraction, transformation, and loading (ETL) solution, analytical processing and data mining capabilities, client analysis tools, and other applications that manage the process of gathering data and delivering it to business users.