Star Schema

Synonyms

Star join schema

Definition

A star schema has one “central” table whose primary key is compound, i.e., consisting of multiple attributes. Each one of these attributes is a foreign key to one of the remaining tables. Such a foreign key dependency exists for each one of these tables, while there are no other foreign keys anywhere in the schema. (In the above, without loss of generality, the assumption is made that all these other tables have simple primary keys. This is usually the case in almost all practical situations, and as for efficiency, these keys are typically generated surrogate keys.)

Key Points

Most data warehouses that represent the multidimensional conceptual data model in a relational fashion [1, 2] store their primary data as well as the data cubes derived from it in star schemas. The “central” table and the remaining tables of the definition above correspond, respectively, to the fact table and the dimension tablesthat are typically found in data warehouses....