Dimensional modeling is a modeling technique that organizes data for analytical system. It is in contrast to entity relationship modeling that is often used in modeling the transactional system.
The objective of dimensional modeling is to design a model that presents the data close to the users’ understanding of their business. A dimensional model separates data into facts and dimensions. Users are allowed to view facts in combinations of dimensions.
See Also: A Dimensional Modeling Manifesto by Ralph KImball