Important: This post was written and published in 2019, and the content below may no longer represent the current capabilities of Power BI. Please consider this post to be an historical record and not a technical resource. All content on this site is the personal output of the author and not an official resource from Microsoft.
I use this diagram a lot:
This diagram neatly summarizes a canonical use case for Power BI dataflows, with source data being ingested and processed as part of an end-to-end BI application. It showcases the Lego-like composition that’s possible with dataflows. But it also has drawbacks – its simplicity omits common scenarios for using and reusing dataflows.
So, let’s look at what’s shown – and at what’s not shown – in my favorite diagram. Let’s look at some of the ways these dataflows and their entities can be used.
- Use the final entities as-is: This is the scenario implied by the diagram. The entities in the “Final Business View” dataflow represent a star schema, and are loaded as-is into a dataset.
- Use the final entities with modification: The entities in the “Final Business View” dataflow are loaded into a dataset, but with additional transformation or filtering applied in the dataset’s queries.
- Use the final entities with mashup: The entities in the “Final Business View” dataflow are loaded into a dataset, but with additional data from other sources added via the dataset’s queries.
- Use upstream entities: The entities in other dataflows are loaded into a dataset, likely with transformations and filtering applied, and with data from other sources added via the dataset’s queries.
Please understand that this list is not exhaustive. There are likely dozens of variations on these themes that I have not called out explicitly. Use this list as a starting point and see where dataflows will take you. I’ll keep the diagram simple, but you can build solutions as complex as you need them to be.
 This is my diagram. There are many like it, but this one is mine.