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Advanced Editor window
Given its importance to the query development process, the Advanced Editor dialog is exposed on both the Home and View tabs of the Query Editor.
It's recommended to use the Query Editor when getting started with a new query and when learning the M language. After several steps have been applied, use the Advanced Editor to review and optionally enhance or customize the M query. As a rich, functional programming language, there are many M functions and optional parameters not exposed via the Query Editor; going beyond the limits of the Query Editor enables more robust data retrieval and integration processes.
Figure 8: The Home tab of the Query Editor
- Click on Advanced Editor from either the View or Home tabs (Figure 8 and Figure 9, respectively).
- All M function expressions and any comments are exposed
Figure 9: The Advanced Editor view of the DimGeography query
When developing retrieval processes for Power BI models, consider these common ETL questions:
- How are our queries impacting the source systems?
- Can we make our retrieval queries more resilient to changes in source data such that they avoid failure?
- Is our retrieval process efficient and simple to follow and support or are there unnecessary steps and queries?
- Are our retrieval queries delivering sufficient performance to the BI application?
- Is our process flexible such that we can quickly apply changes to data sources and logic?
M queries are not intended as a substitute for the workloads typically handled by enterprise ETL tools such as SSIS or Informatica. However, just as BI professionals would carefully review the logic and test the performance of SQL stored procedures and ETL packages supporting their various cubes and reports environment, they should also review the M queries created to support Power BI models and reports.