How to create a RAP-based oData Service and use it in an existing Fiori app that is hosted on FLP?

[mitko1994]

Hello Everyone,

I need your help in rebuilding an existing oData Service using RAP. We currently have some Fiori Apps on FLP which use data coming from the SAP CAR system. The oData services are based on xsodata files on SAP HANA tables. Due to an upcoming upgrade, we need to move the data outside the CAR HANA Layer in order for the apps to continue running. As a result, we would like to leverage RAP and create these tables directly in CAR and create new oData services based on those tables. Currently, when a user runs an app, they are prompted for their HANA credentials in order for the data to be retrieved, but that will now be different.

I must admit I don't have experience with CDS and RAP but based on what I read and saw, the solution steps should be somewhat like the following:

1. Create the tables in CAR
2. Create CDS Entity Views based on the tables
3. Define the Entity behavior and implementation
4. Create the Service Definition and Binding
5. Publish the oData Service
6. Edit the Fiori app to use the new oData Service

Now for my questions...

1. Is the outline above correct?

2. Can I use a managed implementation? If not, why? 

4. How can I define parameters for the Entities and expose them via the service?

3. Should I use a service binding that is UI or API? (I assume API since there is an existing app and I don't want to use Fiori Elements?)

4. How will users be authenticated and authorized to use the service? Is it based on the communication user that is defined for the API service binding?

Thanks in advance.