Book Image

Expert Data Modeling with Power BI

By : Soheil Bakhshi
Book Image

Expert Data Modeling with Power BI

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 data models using Power BI confidently. 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. In this book, you'll explore how to use data modeling and navigation techniques to define relationships and create a data model before defining new metrics and performing custom calculations using modeling features. As you advance through the chapters, the book will demonstrate how to create full-fledged data models, enabling you to create efficient data models and simpler DAX code with new data modeling features. With the help of examples, you'll discover how you can solve business challenges by building optimal data models and changing your existing data models to meet evolving business requirements. 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. 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 reporting and data analytics.
Table of Contents (18 chapters)
Section 1: Data Modeling in Power BI
Section 2: Data Preparation in Query Editor
Section 3: Data Modeling
Section 4: Advanced Data Modeling

Understanding virtual tables

The concept of virtual tables in DAX is somewhat confusing and misunderstood, and yet is one of the most powerful and important concepts of DAX. When we talk about virtual tables, we are referring to in-memory tables that we build using certain DAX functions or constructors. The data in a virtual table is either derived from the data within the data model or the data that we construct for specific purposes.

Remember, whenever we use a DAX function that results in a table of values, we are creating a virtual table.

At this point, you may ask, so when I use a DAX function to create a calculated table, am I creating a virtual table? The answer is it depends. If you simply use a set of DAX functions that generate data or selectively load data from other tables into a calculated table, the answer is no: you have not created any virtual tables. Nevertheless, suppose you generate or load the data from other tables. In that case, you do some table operations...