Book Image

Hands-On Business Intelligence with DAX

By : Horne
Book Image

Hands-On Business Intelligence with DAX

By: Horne

Overview of this book

Data Analysis Expressions (DAX) is known for its ability to increase efficiency by extracting new information from data that is already present in your model. With this book, you’ll learn to use DAX’s functionality and flexibility in the BI and data analytics domains. You’ll start by learning the basics of DAX, along with understanding the importance of good data models, and how to write efficient DAX formulas by using variables and formatting styles. You’ll then explore how DAX queries work with the help of examples. The book will guide you through optimizing the BI workflow by writing powerful DAX queries. Next, you’ll learn to manipulate and load data of varying complexity within Microsoft products such as Power BI, SQL Server, and Excel Power Pivot. You’ll then discover how to build and extend your data models to gain additional insights, before covering progressive DAX syntax and functions to understand complex relationships in DAX. Later, you’ll focus on important DAX functions, specifically those related to tables, date and time, filtering, and statistics. Finally, you’ll delve into advanced topics such as how the formula and storage engines work to optimize queries. By the end of this book, you’ll have gained hands-on experience in employing DAX to enhance your data models by extracting new information and gaining deeper insights.
Table of Contents (18 chapters)
1
Section 1: Introduction to DAX for the BI Pro
7
Section 2: Understanding DAX Functions and Syntax
14
Section 3: Taking DAX to the Next Level

Introducing evaluation contexts – part 2

The word context is derived from the Latin word contextus, which means closely connected or interwoven. In modern language, context is the setting or the set of circumstances around an event.

In DAX, when we talk about the evaluation context, we're talking about the set of circumstances under which a DAX expression is evaluated, brought about by the state of filters, slicers, interactions with visuals, and row and column selections.

In Chapter 1, What is DAX?, we took a brief look at the two types of evaluation context that exist in DAX, which are the following:

  • The row context
  • The filter context

In this chapter, we'll look at these in more detail. We will use examples to help us understand how changes in context change the results that we get back from DAX expressions when they are evaluated within that context.

Strictly...