How To Fix /IWBEP/CM_MGW_RT157 - Type of data container returned by DPC is wrong. '&1' is expected

SAP Error Message - Details

• Message type: E = Error

• Message class: /IWBEP/CM_MGW_RT -

• Message number: 157

• Message text: Type of data container returned by DPC is wrong. '&1' is expected

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message /IWBEP/CM_MGW_RT157 - Type of data container returned by DPC is wrong. '&1' is expected ?

  The SAP error message /IWBEP/CM_MGW_RT157 indicates that there is a mismatch in the type of data container returned by the Data Provider Class (DPC) in an OData service. Specifically, the error message states that the expected type of data container is different from what is being returned.
  Cause:
  
  Mismatch in Data Types: The DPC is expected to return a specific type of data container (e.g., a structure, entity type, or collection), but it is returning a different type.
  Incorrect Implementation: The implementation of the DPC methods (like GET_ENTITY, GET_ENTITYSET, etc.) may not be returning the correct data structure as defined in the service metadata.
  Service Metadata Issues: The OData service metadata might not be correctly defined, leading to discrepancies between what is expected and what is returned.
  Changes in Data Model: If there have been recent changes to the underlying data model or the OData service definition, the DPC might not have been updated accordingly.
  
  Solution:
  
  Check DPC Implementation: Review the implementation of the DPC methods to ensure that they are returning the correct data types as defined in the service metadata. Make sure that the return types match the expected types.
  Review Service Metadata: Check the OData service metadata (usually accessible via the service URL with $metadata appended) to confirm the expected data types and structures.
  Debugging: Use debugging tools to step through the DPC methods to see what data is being returned and compare it with the expected structure.
  Update Data Model: If there have been changes to the data model, ensure that the DPC is updated to reflect these changes. This may involve regenerating the DPC or adjusting the code manually.
  Test with Different Clients: Sometimes, the issue may be client-specific. Test the OData service with different clients (like Postman, SAP Gateway Client, etc.) to see if the issue persists.
  
  Related Information:
  
  SAP Notes: Check for any relevant SAP Notes that might address this specific error or provide guidance on similar issues.
  OData Documentation: Review the SAP OData documentation for best practices on implementing DPCs and handling data types.
  Community Forums: Engage with SAP community forums or support channels to see if others have encountered and resolved similar issues.
  
  By following these steps, you should be able to identify the root cause of the error and implement a solution to resolve it.