Alex Crampton explains how snapshot fact tables work in data warehousing:
The typical fact table measures activities and is known as a transaction fact table. They support a wide variety of analytic possibilities and can be used to capture detailed information about a particular process. Certain facts cannot be studied easily using this kind of design, if at all.
This blog will outline the characteristics of a transaction fact table vs those of a snapshot fact table, and when the need for a snapshot fact table arises.
Snapshot-based fact tables aren’t ideal for data load times (especially as the table gets large) but they are useful in specific circumstances, as Alex points out.