Type of the database which is organised with respect to the certain fragment of reality. The data warehouse is a higher level of the abstraction than the ordinary relation database.

Data set are a member of a wholesale company informed thematically (e.g. data warehouse of customers). This data comes from many sources, they are integrated and intended exclusively for reading. In practice data warehouses are databases integrating data from all remaining systems of databases in the enterprise. This integration consist on cyclical loading the data from production systems into the warehouse. The final users of data warehouse are mostly management.