Star Schema
Star schema is the simplest style of data mart schema in computing. It is an approach which is most widely used to develop data warehouses and dimensional data marts. It features one or more fact tables referencing to numerous dimension tables.
Snowflake Schema
A logical arrangement of tables in a multidimensional database, snowflake schema is represented by centralized fact tables which are connected to multidimensional tables. Dimensional tables in a star schema are normalized using snowflaking. Once normalized, the resultant structure resembles a snowflake with the fact table at the middle. Low-cardinality attributes are removed, and separate tables are formed.
Fact Constellation Schema
Fact constellation schema is a measure of online analytical processing (OLAP), and OLAP happens to be a collection of multiple fact tables sharing dimension tables and viewed as a collection of stars. It can be seen as an extension of the star schema.
