How To Fix /IWBEP/CM_V4_MED236 - Return type of operation '&1': collection of complex types not supported

SAP Error Message - Details

• Message type: E = Error

• Message class: /IWBEP/CM_V4_MED -

• Message number: 236

• Message text: Return type of operation '&1': collection of complex types not supported

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message /IWBEP/CM_V4_MED236 - Return type of operation '&1': collection of complex types not supported ?

  The SAP error message /IWBEP/CM_V4_MED236 indicates that there is an issue with the return type of an operation in an OData service. Specifically, it states that the return type of the operation is a collection of complex types, which is not supported in the context of the operation being executed.
  Cause:
  
  
  Return Type Definition: The operation (such as a function import or an entity set) is defined to return a collection of complex types, but OData services typically do not support returning collections of complex types directly. Instead, they expect either a single entity, a collection of entities, or a primitive type.
  
  
  Service Implementation: The implementation of the OData service may be incorrectly configured to return a collection of complex types instead of a collection of entities or a single entity.
  
  
  Model Definition: The data model defined in the service might be incorrectly set up, leading to the generation of an unsupported return type.
  
  
  Solution:
  
  
  Change Return Type: Modify the return type of the operation in the service definition. Instead of returning a collection of complex types, consider returning:
  
  A collection of entities (if applicable).
  A single complex type (if that fits the use case).
  A primitive type if the operation is meant to return a simple value.
  
  
  
  Adjust Service Implementation: If you are implementing the OData service, ensure that the logic correctly returns the expected type. If you need to return complex data, consider wrapping it in an entity type.
  
  
  Check Metadata: Review the service metadata (usually accessible via the $metadata endpoint) to ensure that the return types are correctly defined and match the expected OData standards.
  
  
  Use Entity Types: If you need to return complex data structures, consider defining them as entity types in your data model. This way, you can return collections of these entities instead of complex types.
  
  
  Testing: After making changes, test the OData service to ensure that the error is resolved and that the expected data is returned correctly.
  
  
  Related Information:
  
  OData Standards: Familiarize yourself with OData standards and specifications, particularly regarding entity types and complex types.
  SAP Gateway: If you are using SAP Gateway, refer to the documentation for guidelines on defining and implementing OData services.
  Debugging: Use transaction codes like /IWFND/ERROR_LOG to check for additional error messages or logs that might provide more context on the issue.
  
  By addressing the return type and ensuring that the service is correctly implemented, you should be able to resolve the error message /IWBEP/CM_V4_MED236.