Part III. Data Modeling for Power BI
with the Help of DAX
Welcome to the DAX part of this book! DAX stands for data analysis expressions and is the language used to create calculated tables, calculated columns, and measures; define row-level security; and query the data inside of Power BI. The latter is done for you by Power BI’s visuals—so most users will have no need to write a DAX query.
If you have read this book from the start, you should now have a good understanding of the importance of the shape of a data model and the need in many situations (if not all!) to reshape what you get from your data source.
This part is not an introduction to the DAX language, but you will learn that data modeling and DAX align very closely. I’ll introduce you to the moving parts of the language in Chapter 9:
Calculated tables
Actively changing relationships for the sake of a calculation
Creating a single primary key
Combining tables in DAX
In Chapter 10, I’ll show you how you can use DAX to reshape your data model:
Normalizing
Denormalizing
Adding calculated columns and measures
Transforming flags and indicators into meaningful text
Building your own date and time tables
Implementing role-playing dimensions
Making the best out of slowly changing dimensions
Flattening parent-child hierarchies
DAX plays an important role in the real-world use cases, discussed in ...
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