Avoiding bidirectional relationships

One of the most misunderstood and somehow misused Power BI features in data modeling is setting the Cross filter direction to Both. This is widely known as a bidirectional relationship. There is nothing wrong with setting a relationship to bidirectional if we know what we are doing and are conscious of its effects on the data model. We have seen Power BI developers who have many bidirectional relationships in their model and consequently end up with many issues, such as getting unexpected results in their DAX calculations or being unable to create a new relationship due to ambiguity.

The reason that overusing bidirectional relationships increases the risk of having an ambiguous model is filter propagation. In Chapter 8, Data Modeling Components, we covered the concept of filter propagation and bidirectional relationships. We looked at a scenario where the developer needed to have two slicers on a report page, one for the product category and...