Thank you for reaching out to the community forum with your question.
I have reviewed the question and am unsure if I fully understood it. Would you mind explaining it in detail?
You can always reach out to Eloqua Support for product related queries:
the database in eloqua is not relational so this is pretty easy.
contacts are related to accounts (you choose the id in the account contact mapping interface)
custom data objects are related to contacts (you choose the id).
objects are not related to objects so that’s pretty much it