Data warehouse

A data warehouse is a relational database that is designed for query and analysis, rather than for transaction processing. It usually contains historical data that are derived from the transaction data, and can include data from other sources too. It separates analysis workload from transaction workload, and enables an organization to consolidate data from several sources.

The schema that is designed for transactional processing is referred as online transaction processing (OLTP). The schema that is designed for analysis purposes is called online analytical processing (OLAP).

Data is extracted from the source or the staging database and necessary transformations are applied to the data. The data is then loaded into the data warehouse database.