Data Modeling with Microsoft Power BI

Chapter 5. Understanding a Power BI Data Model

In this chapter, you will learn how to create a useful data model in Power BI (and the Analysis Services tabular model). This chapter concentrates on the features of the Model view. The following parts of this book discuss options for bringing data of any shape into the desired shape in Power BI (see Chapter 1 for a general description). You will learn that Power BI needs a data model to work.

I will detail the properties tables can have and how to put them into relationships with each other. You’ll find out there’s no need to explicitly mark primary and foreign keys, but you still must be able to identify them to create appropriate relationships. The cardinality of the relationships plays an important role in Power BI. Luckily enough, you don’t need to think about the joins and join path problems too much. You only need to create relationships for your data model. Power BI will automatically use these relationships to join the tables appropriately when the data is queried for a visual. Power BI will also make sure to execute requests against the data in a way that the join path problems do not occur (see “Join Path Problems”).

In this chapter, I reiterate why a single table is not a data model fit for Power BI and that a dimensional model is the go-to solution. Remember: the ultimate goal is to create a data model that makes the report creator’s life easy.

Data Model

To get a visual overview and most of the options needed to create ...