The process of defining your data warehousing system (DWH) has started. You’ve outlined the relevant dimension tables, which tie to the business requirements. These tables definewhatwe weigh, observe and scale. Now we need to definehowwe measure.Fact tables are where we store these measurements. They hold business data that can be aggregated across dimension combinations. But the fact is that fact tables are not so easily described – they have flavors of their own. In this article, we’ll answer some basic questions about fact tables, and examine the pros and cons of each type.