Dear experts,
we are developing a new FIORI application, using as a reference courses from Open.SAP
However, we could not found a solution for our situation:
We have a master-detail application, where Master table and Detail table data structures are defined in ODATA.
We could have two situations, where tables data is enhanced:
1. Customers add z-fields to existing master/detail tables
2. Customers use custom tables with same keys
Could you please explain, how to integrate such situations in our application?
The more detailed, the better 
Best regards,
Denis