Changing relationship behavior

In Chapter 1.2, Model Design, you learned that there can be multiple relationships between tables, but only one of those relationships can be active. The same is true for relationship paths between tables: a Power BI model allows for only one active path between any two tables in the model. This is of course only useful if the inactive relationships can be made active if you need to. You can do this by using the function USERELATIONSHIP.

The function USERELATIONSHIP is used by including it as a filter argument in CALCULATE. This may seem surprising, but it really makes sense. A relationship between a fact table and a filter table ensures that a selection in the filter table propagates to the fact table. Activating another relationship means that that relationship now propagates the selection to the fact table, with the effect that different rows in the fact table are selected. In other words: activating another relationship means changing...