According to the relationship between fact and dimension tables in the design of data warehouse model structure, models can be divided into the star schema and snowflake schema. The star schema is
the simplest style of data warehouse schema.And the star schema is the most commonly used to achieve the data warehouse structure. The star schema consists of one or more fact tables referencing any number of dimension tables. The star schema is an important special case of the snowflake
schema, and is more effective for handling simpler queries.