Data warehousing focuses on data storage. The main source of the data is cleaned, transformed and cataloged and is made available to be used by managers and other business professional for data mining, online analytical processing, market research and decision support (Marakas & OBrien 2009). However, the means to retrieve and analyze data, to extract, transform and load data, and to manage the data dictionary are also considered essential components of a data warehousing system. Many references to data warehousing use this broader context. Thus, an expanded definition for data warehousing includes business intelligence tools, tools to extract, transform and load data into the repository, and tools to manage and retrieve metadata.

Data warehousing arises in an organization's need for reliable, consolidated, unique and integrated analysis and reporting of its data, at different levels of aggregation.