Introduction

Power BI Desktop contains a very rich set of data source connectors and transformation capabilities that support the integration and enhancement of source data. These features are all driven by a powerful functional language and query engine, M, which leverages source system resources when possible and can greatly extend the scope and robustness of the data retrieval process beyond what's possible via the standard query editor interface alone. As with almost all BI projects, the design and development of the data access and retrieval process has great implications for the analytical value, scalability, and sustainability of the overall Power BI solution.

In this chapter, we dive into Power BI Desktop's Get Data experience and walk through the process of establishing and managing data source connections and queries. Examples are provided of using the Query Editor interface and the M language directly to construct and refine queries to meet common data transformation and cleansing needs. In practice and as per the examples, a combination of both tools is recommended to aid the query development process.

A full explanation of the M language and its implementation in Power BI is outside the scope of this book, but additional resources and documentation are included in the There's more... and See also sections of each recipe.