Summary

In this chapter, we defined basic data modeling as a process where you choose which data attributes are grouped into entities and how those entities are related to one another. We learned that for DirectQuery, transformations in Power Query should be kept simple to avoid generating overly complex query statements for the external source system. We also learned how to use the native query viewing feature in Power Query to see the exact query Power BI will use. We saw how transformations can also be translated to native query language.

We learned that Power BI is flexible enough to allow you to define your own relationships across DirectQuery tables not necessarily matching those already in the data source. This must be used with care and some planning. It is better to leverage relationships and referential integrity that are already defined in the external data source where possible as these are likely already optimized for joining and filtering. We also explored relationship...