Fact tables are the heart of your star schema. They are the centerpiece. Without a fact table, you don't have a model; that's why it is very important that you get the facts right from the beginning.
Fact tables represent measurements, or metrics, within your business scope. You can have one or many fact tables, depending on your requirements. When we say fact table, you should think about measurable things, such as sales, quantities, prices, and so on. The fact table will also contain foreign keys to your dimensions.
Foreign keys within the fact table allow linking the data to the dimensions. A primary key in a dimension is a foreign key in the fact table.
A table key univocally identifies one row within a table. When there are ...
