Book Image

Extreme DAX

By : Michiel Rozema, Henk Vlootman
Book Image

Extreme DAX

By: Michiel Rozema, Henk Vlootman

Overview of this book

This book helps business analysts generate powerful and sophisticated analyses from their data using DAX and get the most out of Microsoft Business Intelligence tools. Extreme DAX will first teach you the principles of business intelligence, good model design, and how DAX fits into it all. Then, you’ll launch into detailed examples of DAX in real-world business scenarios such as inventory calculations, forecasting, intercompany business, and data security. At each step, senior DAX experts will walk you through the subtleties involved in working with Power BI models and common mistakes to look out for as you build advanced data aggregations. You’ll deepen your understanding of DAX functions, filters, and measures, and how and when they can be used to derive effective insights. You’ll also be provided with PBIX files for each chapter, so that you can follow along and explore in your own time.
Table of Contents (17 chapters)
Free Chapter
1
Part I: Introduction
6
Part II: Business cases
15
Other Books You May Enjoy
16
Index

Effective model design

The concepts of relationships and filter propagation enable powerful analytics in Power BI models. It is important to think about the design of a model: which tables should the model contain, and which columns need to be in those tables? Which relationships are needed? In short, what is the overall structure of the model? The choices you make in model design will determine what results the model will be able to deliver.

Star schemas and snowflakes

A best practice for analytics using relational databases is to work with a specific database structure, known as a star schema. The basic ideas of star schemas apply to Power BI models as well.

Figure 1.2.12: Generic star schema structure

The central tables in a star schema model are the fact tables. These tables contain things that have happened, will happen, or should happen; like sales transactions, financial ledger transactions, customer inquiries, student enrollments, sales opportunities...