I used SUP for ~half a year now. Most of the tutorials I read focused on connectivity to ordinary database tables. So since this is a product of a SAP company, I wonder, where the tutorials are, which focus on the usage with BAPIs.
Currently, I develop a simple HWC application with 2 MBOs based on 2 BAPIs. There is a one-to-many relationship between both MBOs, so the primary-key attribute of the first MBO is mapped to the load argument of the second MBO. I declared the relationship as 'composite' since HWC only support those types of relationships.
Now I get a warning saying this: Composite relationship from 'mboSapRoute' to 'mboSapZaehlerwechsel' references two mobile business objects in different load groups. For non-database data sources, mobile business objects with a composite relationship should be from the same load group.
I ignored this warning for further development and didn't notice any problems. But it's still a warning and there should be another way to do it right.
Futhermore, I still have some issues at simple operations like UPDATE. While creating the HWC, I just dragged-and-dropped my MBOs in the flow-design-window. SUP then generates automatically a flow. I just added a Online-Request, invoking the findAll object query of the first MBO and leads to the list-first-mbo-screen SUP generated.
The navigation through the two MBOs works perfect, but the UPDATE operation doesn't work at all. If an update is done and submit is executed, the application/unwired server won't call the backend. I noticed, that after I added a dummy-update-operation to the parent MBO (which didn't have one), the backend at least will be called after updating the second MBO (but update values aren't set, though mapped to the keys in the parameter mappings) ... so there seems to be some kind of dependancy of an update operation of a parent MBO update operation. But the parent MBO should not be updatable.
I redesigned the whole scenario using database tables and it all works like a charm. But still I want to use SAP as the backend source.
So I would be thankful for some tips or links to best practices, when it comes to SAP usage in MBOs with all features (relationships, operations, etc.).