Physical and Virtual Relationships in DAX
DAX calculations can leverage relationships present in the data model, but you can obtain the same result without physical relationships, applying equivalent filters using specific DAX patterns. This article show a more efficient technique to apply virtual relationships in DAX expressions.
The more efficient way to apply a relationship between two tables is a physical relationship in the data model. For example, you can have a relationship between Sales and Product using the ProductKey column, as in the following schema.