Data warehouse

A data warehouse is, primarily, a record of an enterprise's past transactional and operational information, stored in a database designed 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 dependent data marts.

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 ETL 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.

There are more than a thousand functioning data warehouse installations in the United states.¹

See also

• Star schema
• Snowflake schema
• Data mining
• Data mart
• Document warehouse
• Executive information system
• OLTP
• OLAP
• Information technology
• Database
• Business intelligence
• Business performance management
• Extract, transform, load

External links

• SearchCRM.com Original daily breaking news, white papers, expert advice, webcasts, product reviews and more on data warehousing.
• Data Warehouse Information and Tools
• Directory of Data Warehouse, Data Mart, Data Mining, and Decision Support Resources
• searchDatabase.com "The term was coined by W. H. Inmon. IBM sometimes uses the term 'information warehouse.'"
• Data.com "Online version of the magazine: networking products and services."

References

¹ Ralph Kimball, The Data Warehouse Lifecycle Toolkit, Wiley, 1998