Using a dataflow as a source for another dataflow

[AndrewZ]

Hi All

We on PowerBI premium and have set up a nice central dataflow for finance that is used by multiple datasets as the one true source of data and its been working well. We have row level security on the various datasets so at present various regions in the world only have access to their data. Now they want to develop further and need to create their own datasets and the best way to do that would be set up another dataflow that is filtered for just that region. I thought it would be simple to create a second dataflow that gets its info from the first but when I try do that power query tells me that linked tables can't be modified and any changes to the query cannot be saved. Am I missing something really obvious or can one dataflow not filter another? The documentation talks about creating and ingesting dataflow and then a ETL one but doesn't say how. I could create a new dataflow that refrences source can be done but its a slow process as there are multiple levels of security and gateways needed so if I can just filter another dataflow it would be much easier.

Thanks

[otravers · Accepted solution]

In your new dataflow, 1) build a first query that references the source dataflow but doesn't load it, 2) reference that query in a second one which you do materialize (i.e. Enable load). This way you're not using Linked Entities and can add filters or any other transformations (in the first or second query, it doesn't really matter).

[lbendlin]

That's not what dataflows are for. They are glorified CSV/Parquet files.  Filtering a dataflow comes with a big performance penalty.  You should do your filtering in the datasets, or consider using datamarts (either on premise or provided by Power BI)