What are data types?
The M language has both values and data types. In the official documentation, data types are formally referred to as types because they don’t just classify data but also classify functions and the data type itself. Throughout this book, we use both the terms data types and types so as not to get confused when comparing them with value types. So, what exactly are data types, and how do they compare to values?
The type system
The type system in Power Query helps classify values, offering information about the structure of your data. When creating custom functions, data types specify the required values. Additionally, they convey essential information to any system into which the data is loaded. Let’s start by delving into an example.
Each kind of value in the M language has a data type. It’s a special kind of value that characterizes the kind of value and carries additional metadata that is specific to the shape of the value. This...
