The Types of Fact Table are
- Snapshot
- Cumulative
- Factless Fact Table
Snapshot
This type of fact table describes the state
of things in a particular instance of time, and usually includes more
semi-additive and non-additive facts. The second example presented here is a
snapshot fact table.
Eg: Daily balances fact can be summed up
through the customers dimension but not through the time dimension.
Cumulative
This type of fact table describes what has
happened over a period of time. For example, this fact table may describe the
total sales by product by store by day. The facts for this type of fact tables
are mostly additive facts. The first example presented here is a cumulative
fact table.
Eg: Sales fact
Factless Fact Table
In the real world, it is possible to have a
fact table that contains no measures or facts. These tables are called
“Factless Fact tables”.
Eg: A fact table which has only
product key and date key is a factless fact. There are no measures in this
table. But still you can get the number products sold over a period of time.
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