How To Fix USMD1621 - Data model &1, entity type &2: Reference attribute &3 is a key field

SAP Error Message - Details

• Message type: E = Error

• Message class: USMD1 - Datenmodel

• Message number: 621

• Message text: Data model &1, entity type &2: Reference attribute &3 is a key field

What causes this issue?

A referencing relationship with the name &V3& was assigned to entity
type &V2& in model &V1&. However, the entity type already has a key
field with the same name. Within an entity type, no referencing
relationship can have the same name as a key field.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

The model cannot be activated.
ELSE
The model cannot be saved.
ENDIF

How to fix this error?

Enter a different name for the referencing relationship.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message USMD1621 - Data model &1, entity type &2: Reference attribute &3 is a key field ?

  The SAP error message USMD1621 typically occurs in the context of SAP Master Data Governance (MDG) when there is an issue with the data model configuration, specifically related to reference attributes and key fields in an entity type.
  Cause:
  The error message indicates that a reference attribute in the specified entity type is being treated as a key field. In SAP MDG, reference attributes are used to link to other entities, but they should not be defined as key fields. Key fields are unique identifiers for records in a database table, while reference attributes are meant to establish relationships between different entities.
  Solution:
  To resolve this error, you should check the configuration of the data model and the entity type mentioned in the error message. Here are the steps you can take:
  
  
  Access the Data Model Configuration:
  
  Go to the SAP MDG configuration transaction (usually MDGIMG or SPRO).
  Navigate to the section where you can manage data models and entity types.
  
  
  
  Identify the Entity Type:
  
  Locate the entity type specified in the error message (replace &2 with the actual entity type name).
  
  
  
  Check the Attributes:
  
  Review the attributes of the entity type and identify the reference attribute mentioned in the error message (replace &3 with the actual reference attribute name).
  Ensure that this reference attribute is not marked as a key field. If it is, you need to change its configuration.
  
  
  
  Modify the Configuration:
  
  If the reference attribute is incorrectly set as a key field, modify its settings to remove the key field designation.
  Save your changes and activate the data model if necessary.
  
  
  
  Test the Changes:
  
  After making the changes, test the data model to ensure that the error no longer occurs when processing data related to the entity type.
  
  
  
  Related Information:
  
  Documentation: Refer to the SAP Help Portal or the specific documentation for SAP MDG for detailed information on data model configuration and best practices.
  SAP Notes: Check for any relevant SAP Notes that might address this specific error or provide additional guidance.
  Community Forums: Consider visiting SAP Community forums or other user groups where similar issues may have been discussed.
  
  By following these steps, you should be able to resolve the USMD1621 error and ensure that your data model is correctly configured.