A data warehouse is a centralized repository of digitally stored business information used to drive reporting and data analysis. It consists of massive quantities of data extracted from numerous sources, such as relational databases, internal applications, transactional systems, and external partner systems, aggregated into unified, well-structured historical data.
Data warehouse is usually populated with data from an operational database, which contains transactions. The process of populating the data warehouse is called Extract, Transform, and Load (ETL). This process cleans, transforms, and loads the data into the data warehouse. Once the data is in the data warehouse, it can be used for reporting and analysis.
Data warehouses are used to support business intelligence applications. Business intelligence applications are used to make decisions about the operation of the business. Lets discuss more about Data warehouses in next articles.