What is a Data Warehouse?

What is a Data Warehouse?

One of the most important assets of any organization is its information. This asset is almost always kept by an organization in two forms: the operational systems of record and the data warehouse. The operational systems are where the data is put in, and the data warehouse is where we get the data out.

 

In an operational system users takes orders, sign up new customers, and log complaints. They almost always deal with one record at a time in an operational system. They repeatedly perform the same operational tasks over and over. On the other hand, the users of a data warehouse watch the wheels of the organization turn. They count the new orders and compare them with last week's orders and ask why the new customers signed up and what the customers complained about. Users of a data warehouse almost never deal with one row at a time. Rather, their questions often require that hundreds or thousands of rows be searched and compressed into an answer set. To further complicate matters, users of a data warehouse continuously change the kinds of questions they ask.

 

A data warehouse is a central repository for all or significant parts of the data that an enterprise's various business systems collect. Typically, a data warehouse is housed on an enterprise mainframe server. Data from various online transaction processing (OLTP) applications and other sources is selectively extracted and organized on the data warehouse database for use by analytical applications and user queries.