Dimensional Modeling, Star, and Snowflake Schemas
Definition of Dimensional Modeling
According to Ralph Kimball, the creator of the dimensional modeling methodology, “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” (Kimball, 1997).
The graphic indicates a simplified example of a fact table (Product) and its associated dimension tables (Division, Department, Class, Item, UPC, and Subclass).