Forum Discussion
Rebuild this data combination message
Ah, the formula firewall.
The short version of what is happening is that Power BI is very helpfully attempting to stop you from inadvertently passing data from one data source into another source, which happens to be exactly what you want to do, and are deliberately doing. This is intended to safeguard folks from pulling privileged data from one system, and through Power Query's folding mechanism having this data pushed out to another external system without them knowing; inadvertently causing a security breach.
The first thing to try in this case is to break your query into two pieces. I see that you've done this already with your source step being KB4TrainigCampaigns, but give this a try:
In the query editor (not the advanced editor) on the applied steps, right-click on your custom function step, and select 'Extract Previous'. This is going to break your query into two pieces, the first being the transformations to your initial data, and the second being only the call to the external source.
In MOST cases, this is enough to eliminate the formula firewall issue.
Doing this did not change anything. I am still getting the same error.
Ok, if this were a SQL datasource, you could get around it by using Value.NativeQuery; but it isn't.
Bear with me, because my next suggestion sounds totally stupid, but it might work. Prior to your 'Source' step, try pulling the string out of the parameter, and THEN passing it to the API call.
Something like:
this_campaign = CampaignIdand then refer to this_campaign instead of the parameter directly.
My thinking here is that the engine is nesting your outer query into your inner query, which isn't allowed, so we're forcing it to evaluate first before passing the evaluated value into the API call.
No joy. Still encountering the same error.
