This depends a bit on your use case and what which way the association (relationship) goes.
A couple of tips:
- If the data is based on user input you can add a reference selector(or different UI) to a page so that the user can populate the assocation
- If you are doing some sort of processing microflow then you can indeed loop over 1 side of the entities and associate them to the correct other entity. Depending on what the association is 1-1, 1-* or *-* , you can determine which entity to loop over.
Setting the association in a microflow is nothing more then a change activity and set the association EntityA_EntityB with object $EntityB for example.
Hope this helps!
There is no such feature in Mendix, but that’s exactly why the Migration module :exist : https://marketplace.mendix.com/link/component/120423