A data warehouse is a storage architecture designed to hold data extracted from transaction systems, operational data stores and external sources. The warehouse then combines that data in an aggregate, summary form suitable for enterprisewide data analysis and reporting for predefined business needs.
The five components of a data warehouse are:
Production data sources
Data extraction and conversion
Data warehouse database management system
Data warehouse administration
Business intelligence (BI) tools
A data warehouse contains data arranged into abstracted subject areas with time-variant versions of the same records, with an appropriate level of data grain or detail to make it useful across two or more different types of analyses most often deployed with tendencies to third normal form. A data mart contains similarly time-variant and subject-oriented data, but with relationships implying dimensional use of data wherein facts are distinctly separate from dimension data, thus making them more appropriate for single categories of analysis.