Data warehouse

A data warehouse is, primarily, a record of an enterprise s past transactional and operational information, stored in a Database database design to favour efficient data analysis and reporting (especially OLAP). Data warehousing is not meant for current "live" data.

Data warehouses often hold large amounts of Information which are sometimes subdivided into smaller logical units called data mart.

Usually, two basic ideas guide the creation of a data warehouse:

Integration of data from distributed and differently structured databases, which facilitates a global overview and comprehensive analysis in the data warehouse.

Separation of data used in daily operations from data used in the data warehouse for purposes of reporting, decision support, analysis and controlling.

Periodically, one imports Data from enterprise resource planning (ERP) systems and other related business software systems into the data warehouse for further processing. It is common practice to stage Data prior to merging it into a data warehouse. In this sense, to stage data means to queue it for preprocessing, usually with an Extract, transform, load tool. The preprocessing program reads the staged data (often a Business s primary OLTP databases), performs qualitative preprocessing or filtering (including Denormalization, if deemed necessary), and writes it into the warehouse.

=See also=

*Business intelligence *Business performance management *Data mart *Data mining *Database management system *Executive information system *Extract, transform, load *Intelligent document *Master Data Management *OLAP *OLTP *Open source olap *Operational data store *Snowflake schema *Star schema

=References=

*Pyle, Dorian. Business Modeling and Data Mining . Morgan Kaufmann, 2003. ISBN 155860653X