What is Fact Table?

Fact table stores the measures of the business process event and associates them with the descriptive context (dimension tables). So, there are two kinds of elements contained in the fact table. They are the measures (usually numeric, e.g. UnitSold, AmountSold) and the dimension key.

The row in the fact table is representing the defined grain of it. For example, if we define the grain as "Sales invoice", the fact table may contain DateKey, StoreKey, SalesPersonKey, UnitSold and AmountSold. Otherwise, if the grain is "Sales Invoice Line", the fact tables may contain DateKey, StoreKey, SalesPersonKey, ProductKey, LineNum, UnitSold and AmountSold.

There are various techniques for modeling fact tables as below. We will briefly describe them in the coming posts.

• Measures:
• Measure: Additive, Semi-additive and non-additive
• Factless Fact Table
• Grain of the Fact Table
• Three basic forms of Fact Table
• Transactional Fact Table
• Periodic Snapshot Fact Table
• Accumulating Snapshot Fact Table
• Derived Fact Tables
• Aggregated Fact Table
• Consolidated Fact Table