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

Data type conversion

Data type conversion is one of the most common steps we take in Power Query, yet it is one of the most important ones that can become tricky when it's not managed well. One cool feature of Power BI, if enabled, is that it can detect data types automatically. While this is a handy feature in many cases, it can be the root cause of some issues down the road. The critical point to note is how Power BI automatically detects data types. Power BI automatically detects column data types based on the first few hundred rows.

This is when things can go wrong, as the data types are not detected based on the whole dataset. Instead, the data types are detected based on part of it. In most cases, we deal with data type conversion in table values. Either we use the Power Query Editor UI or manually write the expressions; here, we use the following function:

Table.TransformColumnTypes(Table as table, TypeTransformations as list, optional Culture as nullable text)