On the outlook it seems an interesting term but also
contradictory.
A confusion arises straightaway; Is it a fact? But the
term says factless!!
Before we get to the definition of factless facts, let’s
quickly revisit the definition of fact tables- “Fact Tables
consist of the measurements or metrics of a business process”
Now let’s look into in the definition of Factless
Facts and seize the difference.
“Factless fact table is a fact table that does not
contain any quantitative measures and are so called because they simply contain
keys which refer to the dimension tables”.
(There are some tables that may not contain any
straightforward measures like SalesAmount or QuantitySold, however they contain
relations between Dimensionskeys and are facts in themselves).
Let us see the
below example to ease the understanding:
Consider the scenario where a Project Manager wants to
track the details of the leave taken by his team member during a certain
period.
As we can see that there is one fact table
(Fact_Employee_Leave_Type) in the center which mapped to 3 dimensional tables.
The Fact table has no measures but still it provides a
detail of employee taking a leave on particular day and its type.
*Tracking the no. of leaves taken by employees is
helpful. But the real analysis will based on the type of leaves taken by
employee helping the managers/stakeholders to take appropriate decisions.
