How To Fix /IWBEP/CM_V4_MED130 - Ref. constr.: Navigation property '&1' in '&2' targets collection

SAP Error Message - Details

• Message type: E = Error

• Message class: /IWBEP/CM_V4_MED -

• Message number: 130

• Message text: Ref. constr.: Navigation property '&1' in '&2' targets collection

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message /IWBEP/CM_V4_MED130 - Ref. constr.: Navigation property '&1' in '&2' targets collection ?

  The SAP error message /IWBEP/CM_V4_MED130 indicates that there is an issue with a navigation property in an OData service. Specifically, the error message states that the navigation property &1 in the entity &2 targets a collection, which means that the property is expected to return multiple values (a collection) but is being treated as a single value.
  Cause:
  
  Incorrect Data Model Configuration: The navigation property is defined as a collection in the data model, but the code or the OData service is trying to access it as a single entity.
  Service Implementation Issues: The implementation of the OData service may not correctly handle the navigation property, leading to a mismatch between the expected and actual data types.
  Query Issues: The OData query being executed may be incorrectly formed, attempting to retrieve a single entity instead of a collection.
  
  Solution:
  
  Check the Data Model: Review the data model definition in the SAP backend (e.g., using SEGW transaction) to ensure that the navigation property is correctly defined as a collection.
  Adjust the OData Query: If you are making an OData request, ensure that the query is correctly structured to handle collections. For example, if you are trying to access a collection, use the appropriate syntax (e.g., /EntitySet('key')/NavigationProperty).
  Modify Service Implementation: If you are developing or maintaining the OData service, ensure that the implementation correctly returns a collection for the navigation property. This may involve modifying the code in the service implementation class.
  Test with Different Scenarios: Test the OData service with different scenarios to ensure that it behaves as expected when accessing the navigation property.
  
  Related Information:
  
  OData Documentation: Review the OData documentation for guidelines on defining and using navigation properties.
  SAP Notes: Check for any relevant SAP Notes that may address known issues or provide additional guidance on this error.
  Debugging: Use debugging tools in SAP (e.g., transaction SE80 or SEGW) to trace the execution of the OData service and identify where the mismatch occurs.
  
  By following these steps, you should be able to identify the root cause of the error and implement a solution to resolve it.