Book Image

Expert Data Modeling with Power BI - Second Edition

By : Soheil Bakhshi
4 (1)
Book Image

Expert Data Modeling with Power BI - Second Edition

4 (1)
By: Soheil Bakhshi

Overview of this book

This book is a comprehensive guide to understanding the ins and outs of data modeling and how to create full-fledged data models using Power BI confidently. In this new, fully updated edition, you'll learn how to connect data from multiple sources, understand data, define and manage relationships between data, and shape data models to gain deep and detailed insights about your organization. As you advance through the chapters, the book will demonstrate how to prepare efficient data models in the Power Query Editor and use simpler DAX code with new data modeling features. You'll explore how to use the various data modeling and navigation techniques and perform custom calculations using the modeling features with the help of real-world examples. Finally, you'll learn how to use some new and advanced modeling features to enhance your data models to carry out a wide variety of complex tasks. Additionally, you'll learn valuable best practices and explore common data modeling complications and the solutions to supercharge the process of creating a data model in Power BI and build better-performing data models. By the end of this Power BI book, you'll have gained the skills you need to structure data coming from multiple sources in different ways to create optimized data models that support high-performing reports and data analytics.
Table of Contents (22 chapters)
1
Section I: Data Modeling in Power BI
4
Section II: Data Preparation in Query Editor
10
Section III: Data Modeling
13
Section IV: Advanced Data Modeling
20
Other Books You May Enjoy
21
Index

Define key columns in queries

One of the most important aspects of a relational database is defining key columns. The key columns are the columns used to define a relationship between two tables. The key column(s) in a table guarantees the uniqueness of each row of data. The key column guaranteeing the uniqueness of each row within a table is the primary key. The primary key of a table appearing in another table is called a foreign key. In many cases, a single column does not guarantee the uniqueness of rows, but the so-called Composite Key does by considering multiple columns as key columns. The xVelocity engine in the data model layer, as we discuss in more detail in Chapter 8, Data Modeling Components, does not support composite keys, but the Power Query engine does. By defining the key columns in the Power Query Editor, we get some performance gains in refreshing the data, especially when merging two tables. We discussed merging tables in Chapter 5, Common Data Preparation Steps...