пятница, 19 сентября 2014 г.

What is Star Schema?

The first thing you might ask is: Why are these database models called ‘‘star schema’’? Probably because the entity-relationship diagram of this kind of schema resembles a star. The center of the star consists of a large fact table and the points of the star are the dimension tables. Most users first encounter a star schema in a sales data mart with customers, products, stores, promotions, and time.

It’s the modeling technique that counts, not the number of dimension tables used. One of the obvious benefits of using a schema like this is its simplicity and understandability for end users. Very often during the design phase of a data warehouse, star schemas are used to draw the initial translation of business questions into logical database diagrams.