Some update:
One additonal problem occures when versioning the Item. Here Component Engineering also needs the add access to add the new relationship.
Lock and Unlock also needs special handling, as in my example the costs shall be completly separated from the Part. Null-relationships are not intended to support this behaviour.
It really requires a lot of Methods to handle all possibly situations than can occur.
But maybe I found the ultimate best solution: Federated relationship inside the Aras db.
1. Create a new Itemtype (e.g. MyGoals) for storing the costs.
2. This new ItemType must contain the same properties like Part Goal. So we have to add properties for "source_id", "actual_value", ...
3. Add an onGet Method in Part Goal that takes the values from MyGoals
This way we can achieve a hard separation of Parts and Costs. Both can be added and edited separately. We can use complete different permissions models, without getting into trouble when version or copy an Item.
I really like this soluton! But I would be happy to hear any second opinion when it comes to this use case.
