CPI/BTP

To me, useOneAsMany is to BTP Mappings what offside is in soccer: incredibly difficult to understand or explain to a newcomer.

I don't need to use it everyday, so I keep forgetting how it works myself - at the same time, I find the various explanations out there very complicated and hard to follow. So I'll give it a try myself, hoping it will at least help me remember next time I need to use it:

In short: useOneAsMany allows you to reuse a field that occurs only once in a context that occurs multiple times. Think header field on item level.

As we all know, SAP has changed the way exchange rates are replicated with the transition to S/4. In ERP, C4C would pull the exchange rates using a background job. In S/4, the exchange rates are pushed to C4C using a new interface.

When you maintain a communication system in SAP C4C for integration with an SAP backend system (ERP, S/4), you flag the "SAP Business Suite" field and then maintain the "Business Instances".

The terminology has always confused me, but I just came across a pretty old blog by SAP that explains these fields under a somewhat unintuitive title: Communication System Setup and Message Header Hand... - SAP Community.

As C4C development systems (that are in development) use a different namespace than non-dev systems, simply copying or transporting an iflow from DEV to TEST (or PROD) will lose all extension field mappings.

You can either adjust your iflows manually. This involves uploading the test system WSDL to the iflow and re-mapping all extension fields from the DEV namespace to the test/production namespace, which is not recommended as it is very error-prone.

However, you can also do this automatically with a one-line change as follows:

WSDLs for an IDOC can be downloaded in transaction WE62.

Simply enter the IDOC type and click Documentation --> Download XML Schema

If you get the error "Segment X is unknown in release Y" (EA 257), it generally means that the segment in question has not been released. If it's a custom IDOC you've built or generated yourself, you can do the release in BDFG or WE30.

Anybody ever looking for a list of standard CPI message headers and properties:

https://help.sap.com/docs/cloud-integration/sap-cloud-integration/headers-and-exchange-properties-provided-by-integration-framework

These properties can be used, for instance, in Groovy functions like this (where SAPMessageID is the property from above link):