We covered in the previous chapter that Power BI has different layers: data preparation, data modeling, and data visualization. This chapter discusses Data Analysis eXpressions (DAX), and it relates to data modeling. Although data modeling and DAX are connected such that you cannot imagine one without the other, our goal in this book is not to focus only on DAX. Data modeling encompasses much broader concepts, while DAX is the expression language that developers must use to implement business logic in the data model. Our assumption in this book is that you have basic to intermediate knowledge of DAX; therefore, we will not cover basic DAX concepts. Instead, we will focus on more advanced DAX concepts with hands-on scenarios.
This chapter covers the following topics:
- Understanding virtual tables
- Relationships in virtual tables
- Time intelligence