How To Fix MC731 - Required field &-& is not a key field

SAP Error Message - Details

• Message type: E = Error

• Message class: MC - Aggregate: views, matchcodes, lock objects

• Message number: 731

• Message text: Required field &-& is not a key field

What causes this issue?

Certain key fields of the primary and secondary tables must be included
as key fields of the view in order to ensure an unambiguous key for the
view.
The specified field is contained in the view but was not marked as a
key field.
For fields which are linked with a join, the field of a secondary table
which is connected with the key field of the primary table can be
included in the view instead of the key field of the primary table
itself. However, this means that this field will not be marked as a key
field, causing this message.

System Response

The view is activated. Errors can occur during maintenance with
transaction SM30.

How to fix this error?

We recommend that you keep the key fields suggested by the system
in the view.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message MC731 - Required field &-& is not a key field ?

  The SAP error message MC731, which states "Required field &-& is not a key field," typically occurs in the context of data entry or configuration in the SAP system, particularly in the area of Material Management (MM) or Logistics. This error indicates that a required field is not defined as a key field in the relevant table or structure, which is necessary for the operation you are trying to perform.
  Cause:
  
  Missing Key Field: The field that is required for the operation is not defined as a key field in the database table or structure.
  Configuration Issues: There may be issues in the configuration of the material master, info records, or other related master data.
  Data Entry Errors: The user may be trying to enter data in a way that does not comply with the expected structure or requirements of the system.
  
  Solution:
  
  Check Configuration: Review the configuration settings for the relevant master data (e.g., material master, info records) to ensure that all required fields are correctly defined as key fields.
  Review Data Entry: Ensure that the data being entered complies with the expected format and that all required fields are filled out correctly.
  Consult Documentation: Refer to SAP documentation or help resources to understand the specific requirements for the fields in question.
  Use Transaction Codes: If applicable, use transaction codes like MM01 (Create Material), MM02 (Change Material), or others relevant to your context to check the field settings.
  Contact SAP Support: If the issue persists and you cannot identify the cause, consider reaching out to SAP support or your internal SAP team for further assistance.
  
  Related Information:
  
  Field Definitions: Understanding the definitions and roles of key fields in SAP can help in troubleshooting this error.
  SAP Notes: Check for any relevant SAP Notes that may address this specific error or provide additional guidance.
  User Roles and Authorizations: Ensure that the user has the necessary authorizations to perform the actions related to the required fields.
  Testing in Development: If you are in a development environment, test changes before applying them to production to avoid disruptions.
  
  By following these steps, you should be able to identify the cause of the MC731 error and implement a solution to resolve it.