RAP Service Unmanaged Save with CDS Parameters

[axel_brke3]

We want to create a RAP Service using a CDS View which relies on Parameters.

define root view entity ZTEST_CO_VIEW
  with parameters
    p_fiscalYear        : gjahr
  as select from ZTEST_CI_VIEW(  p_fiscalYear : $parameters.p_fiscalYear )
{       
    key matnr,
    field1,
    field2
}

However, when creating a behavior for this View and exposing as a Service (we would like to use unmanaged Save), we get the following error message:

Non-hidden view parameters are not allowed in transactional entity ZTEST_CO_VIEW

Am I right to understand that I cannot use CDS View Parameters with Behaviors?

Does someone know if this is documented somewhere?

Thanks and regards,

Axel

[LuisBecker1]

I have exactly the same issue and even after reading every SAP documentation possible couldn't find a way to solve it. Unfortunately the SAP Community seems to have "died" and it's hard to get help. Let me know if you had any luck finding a solution.

[Marian_Zeis]

I´ve never tried to create a View with Paramters but heard only bad things, what is the use case, why do you need the parameter @LuisBecker1

[LuisBecker1]

@Marian_Zeis, the parameter is needed because I'm consuming a SAP standard CDS view with parameters (I_AssetBalanceCube). The most bizarre fact is when I bind a service and do a Fiori app preview, it creates a mandatory filter and works. When I generate a List Report Fiori Elements, it doesn't work at all. Tried several solutions to either passe the parameter from the Fiori app or to derive from another field/CDS view and nothing worked.

[Marian_Zeis]

@LuisBecker1  what about wrapping the SAP CDS View in a Custom CDS View? Could that work? Bad workaround would be unmanaged service with custom read 😕

[axel_brke3]

@Marian regarding your questions why parameters are used: when designing Data models, parameters are a very powerful tool for performance optimizations because they allow to push down where conditions to table level by design. We have made huge improvements to complex data models using parameters. I actually would like to strongly encourage usage of paramaters for all data models in our company, but unfortunately they have a lot of restrictions. Also navigation via Associations via ODATA does not work with parameters 😞

[LuisBecker1]

@Marian_Zeis even wrapping the function, still need to derive or get the parameter for somewhere. As in this case is fiscal year, there's no system environment. We had to do an unmanaged service because it's not only a read, it also has two function calls. Could have done two separated services but it would be an overkill. Also it didn't work when it was a single service with binding/definition (no behaviour definition or anything from RAP). And unfortunately SAP's documentation is superficial, to say the less.