Dimensional modeling is the name of a logical design technique often used for data warehouses. DM is the only viable technique for databases that are designed to support end-user queries in a data warehouse. It is different from, and contrasts with, entity-relation modeling. ER is very useful for the transaction capture and the data administration phases of constructing a data warehouse, but it should be avoided for end-user delivery. This paper explains the dimensional modeling and how dimensional modeling technique varies/ contrasts with ER models.
Dimensional Modeling is a favorite modeling technique in data warehousing. DM is a logical design technique that seeks to present the data in a standard, intuitive framework that allows for high-performance access. It is inherently dimensional, and it adheres to a discipline that uses the relational model with some important restrictions. Every dimensional model is composed of one table with a multipart key, called the fact table, and a set of smaller tables called dimension tables. Each dimension table has a single-part primary key that corresponds exactly to one of the components of the multipart key in the fact table. This characteristic “star-like” structure is often called a star join. A fact table, because it has a multipart primary key made up of two or more foreign keys, always expresses a many-to-many relationship. …