A common form of dimensional model. In a snowflake schema, different hierarchies in a dimension can be extended into their own dimensional tables. Therefore, a dimension can have more than a single dimension table.
An extension of a star schema such that one or more dimensions are defined by multiple tables. In a snowflake schema, only primary dimension tables are joined to the fact table. Additional dimension tables are joined to primary dimension tables.
A snowflake schema is a set of tables comprised of a single, central fact table surrounded by normalized dimension hierarchies. Each dimension level is represented in a table. Snowflake schema implement dimensional data structures with fully normalized dimensions. Star schema are an alternative to snowflake schema.
The snowflake schema is a variation of the star schema used in a data warehouse. The snowflake and star schema are methods of storing data which are multidimensional in nature (i.e. which can be analysed by any or all of a number of independent factors) in a relational database.