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

Reducing model size by disabling auto date/time

When the data is loaded into the data model, Power BI automatically creates some Date tables to support calendar hierarchies for all columns in DateTime datatype. This feature is convenient, especially for beginners who do not know how to create a Date table or create and manage hierarchies. However, it can consume too much storage, which can potentially lead to severe performance issues. As mentioned earlier, the auto date/time feature forces Power BI Desktop to create Date tables for every single DateTime column within the model. The Date tables have the following columns:

  • Date
  • Year
  • Quarter
  • Month
  • Day

The last four columns are used to create date hierarchies for each DateTime column. The Date column in the created Date table starts from January 1 of the minimum year of the related column in our tables. It ends on December 31 of the maximum year of that column. It is a common practice in data warehousing...