A Star Schema is a special form of an Entity Relation Diagram(ERD). It is used to represent multidimensional structures in databases. The name Star Schema (the Anglicism is more common than the German term Stern-Schema) is derived from its graphical form. In a Star Schema there is always a central fact table surrounded by one or more dimension tables, thus representing a multidimensional structure as used e.g. in Online Analytical Processing( OLAP).
In the Star schema, only the central table is connected to all other tables. The "outer" tables have no direct connections to each other. This central fact table contains the key figures and detail attributes, while the surrounding dimension tables contain the key and property attributes that describe the business context of the data in the fact table.
In OLAP, we therefore speak of nodes of the dimensions to which the key figures of the fact table are assigned. In this context, we refer to the term OLAP cube. Such a cube can always be represented by a star schema. The star schema is closely related to the snowflake schema.