Four different views regarding the design of a data warehousemust be considered: the top-down view, the data source view, the data warehouse view, and the business query view.
The top-down view allows the selection of the relevant information necessary for the data warehouse. This information matches the current and future business needs.
The data source view exposes the information being captured, stored, and managed by operational systems. This information may be documented at various levels of detail and accuracy, from individual data source tables to integrated data source tables. Data sources are often modeled by traditional data modeling techniques, such as the entity-relationship model or CASE (computer-aided software engineering) tools.
The data warehouse view includes fact tables and dimension tables. It represents the information that is stored inside the data warehouse, including precalculated totals and counts, as well as information regarding the source, date, and time of origin, added to provide historical context.
Finally, the business query view is the perspective of data in the data warehouse from the viewpoint of the end user.