BI: Dimensional Model - Fact Constellation schema architecture

Fact Constellation schema: 
As its name implies, it is shaped like a constellation of stars (i.e., star schemas). This schema is more complex than star or snowflake varieties, which is due to the fact that it contains multiple fact tables. This allows dimension tables to be shared amongst the fact tables. A schema of this type should only be used for applications that need a high level of sophistication.

BI: Dimensional Model - Snowflake schema architecture

Snowflake schema architecture is a more complex variation of a star schema design. The main difference is that dimensional tables in a snowflake schema are normalized, so they have a typical relational database design.

BI: Dimensional Model - Star Schema

The star schema is the simplest style of data warehouse schema. The star schema consists of a few fact tables (possibly only one) referencing any number of dimension tables.

Star Schema Format 1:

Star Schema Format 2:

Star Schema Format 3:

Star Schema Format 4: