I made some progress. I solved the original use case by making an additional SQL view. Not my favorite solution, but this way I was able to read the data with a much simpler AML query.
But this topic is still a rabbit hole regarding the query definition.
I so far didn´t succeed in using my federated ItemType inside a QD. Even if I create a completely new QD with just the Federated ItemType I get the "<faultstring>Item attribute 'itemTypeName' not set !</faultstring>" error message.
And I think I know the reason. QDs work different than the Grid. Right know my federation onGet query is optimized for the classic "Grid - Relationship - Form" trinity. But QDs work different, as they support more additional functionality like levels and reverse properties. My Federated ItemType cannot work, cause it doesn't provide the data that a QD needs. I right now just return the regular item structure but QDs works a lot with references.
eli_donahue Do you know if there is any information of the basic data structure a Query Definition uses when pulling data? It´s not an important topic right now, but I see a lot of fun use cases for these kind of queries.
I can check with the PM and architect for QD to see if we have any info to share. Using federated data in QD’s certainly sounds like a helpful use case.
PS: “We have an item property at home” gave me a good laugh [emoticon:752f32bcc91d4a448db162742a877a4a]
