The fact table is the central table in a dimensional model. It contains the additive or factual data about a business that can help you answer your business questions. It brings together data that would reside in multiple tables throughout the database in traditional relational databases.
Fact tables and dimension tables are related by identifying relationships, so that the primary key of the dimension tables migrate to the primary key of the fact table as foreign keys.
In the example below, the REVENUE fact table's primary key is composed of four foreign keys: movie_key, customer_key, market_key, and time_key. The fact table's primary key is made up of the primary keys of all the dimension tables. The primary key of the REVENUE fact table, which is a concatenation of the primay keys of the dimension tables, can uniquely identify each row.
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