How To Fix /IWBEP/CM_V4_MED194 - Target multiplicity '&1' is not allowed for navigation property '&2'

SAP Error Message - Details

• Message type: E = Error

• Message class: /IWBEP/CM_V4_MED -

• Message number: 194

• Message text: Target multiplicity '&1' is not allowed for navigation property '&2'

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message /IWBEP/CM_V4_MED194 - Target multiplicity '&1' is not allowed for navigation property '&2' ?

  The SAP error message /IWBEP/CM_V4_MED194 indicates that there is an issue with the target multiplicity of a navigation property in an OData service. This error typically arises when the multiplicity defined in the OData model does not match the actual data model or the expected relationships between entities.
  Cause:
  
  Multiplicity Mismatch: The error occurs when the navigation property is defined with a multiplicity that does not align with the underlying data model. For example, if a navigation property is defined as a one-to-many relationship but the actual data indicates a one-to-one relationship, this error will be triggered.
  Incorrect Model Definition: The OData service might have been incorrectly defined in the metadata, leading to inconsistencies between the service definition and the actual data structure.
  Data Inconsistency: The data in the database might not conform to the expected relationships defined in the OData model.
  
  Solution:
  
  Check the OData Model: Review the OData service definition in the SAP Gateway Service Builder (transaction code SEGW). Ensure that the navigation properties are defined correctly with the appropriate multiplicity (1:1, 1:n, n:m).
  Adjust the Data Model: If the navigation property is defined correctly but the underlying data model is incorrect, you may need to adjust the database schema or the data itself to ensure it aligns with the OData model.
  Update the Service: If changes are made to the model, regenerate the service and update the metadata to reflect the changes. This can be done in the Service Builder by right-clicking on the service and selecting "Generate Runtime Objects."
  Test the Service: After making the necessary adjustments, test the OData service to ensure that the error no longer occurs and that the navigation properties work as expected.
  
  Related Information:
  
  
  OData Multiplicity: Understanding the concept of multiplicity in OData is crucial. It defines how many instances of an entity can be related to another entity. Common multiplicities include:
  
  1:1 (one-to-one)
  1:n (one-to-many)
  n:m (many-to-many)
  
  
  
  SAP Gateway: Familiarize yourself with the SAP Gateway framework, which is used to create OData services. The Service Builder (SEGW) is a key tool for defining and managing these services.
  
  
  Debugging: If the issue persists, consider using transaction code /IWBEP/ERROR_LOG to check for additional error details that might provide more context on the problem.
  
  
  By following these steps, you should be able to resolve the error and ensure that your OData service functions correctly.