How To Fix USMD1557 - Data model &1: Key attributes must not be assigned to entity type &2

SAP Error Message - Details

• Message type: E = Error

• Message class: USMD1 - Datenmodel

• Message number: 557

• Message text: Data model &1: Key attributes must not be assigned to entity type &2

What causes this issue?

The &V3& attribute is defined as key field. This is not allowed for
attributes of entity types of storage and usage type 4.

System Response

The system does not save or activate the data model.

How to fix this error?

In the <LS>Attributes </>view, deselect <LS>Key Field</> for the &V3&
attribute.
If you want to create a key field for the &V2& entity type, choose the
<LS>Relationships </>view.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message USMD1557 - Data model &1: Key attributes must not be assigned to entity type &2 ?

  The SAP error message USMD1557 indicates that there is an issue with the assignment of key attributes in a data model. Specifically, it states that key attributes must not be assigned to a certain entity type. This error typically arises in the context of SAP Master Data Governance (MDG) or similar data modeling scenarios.
  Cause:
  The error occurs when you attempt to assign key attributes to an entity type that does not support them. In SAP data modeling, key attributes are used to uniquely identify instances of an entity. However, certain entity types may not be designed to have key attributes, leading to this error.
  Solution:
  To resolve the error USMD1557, you can follow these steps:
  
  
  Review the Entity Type: Check the entity type mentioned in the error message. Ensure that it is appropriate for key attributes. Some entity types may be designed to have only non-key attributes.
  
  
  Modify the Data Model:
  
  If the entity type is not supposed to have key attributes, remove the assignment of key attributes from that entity type.
  If the entity type should have key attributes, consider changing its definition or structure to accommodate them.
  
  
  
  Check Data Model Configuration: Ensure that the data model configuration aligns with the business requirements and the intended use of the entity types.
  
  
  Consult Documentation: Refer to SAP documentation or guidelines related to data modeling in MDG to understand the constraints and requirements for key attributes and entity types.
  
  
  Testing: After making the necessary changes, test the data model to ensure that the error is resolved and that the data model functions as expected.
  
  
  Related Information:
  
  SAP Master Data Governance (MDG): This is the primary context in which this error may occur. Understanding the principles of MDG and how data models are structured can help in troubleshooting.
  Entity Types and Attributes: Familiarize yourself with the different types of entities and their attributes in SAP. This knowledge can help you design your data model correctly.
  SAP Community and Support: If you continue to face issues, consider reaching out to the SAP Community or SAP Support for further assistance. They can provide insights based on similar experiences from other users.
  
  By following these steps, you should be able to resolve the USMD1557 error and ensure that your data model is correctly configured.