How To Fix /UI2/PAGE021 - Key fields must not be changed

SAP Error Message - Details

• Message type: E = Error

• Message class: /UI2/PAGE -

• Message number: 021

• Message text: Key fields must not be changed

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message /UI2/PAGE021 - Key fields must not be changed ?

  The SAP error message /UI2/PAGE021 Key fields must not be changed typically occurs in the context of SAP Fiori applications or when working with SAP UI5 applications. This error indicates that there is an attempt to modify key fields in a data model that should remain unchanged. Key fields are essential for uniquely identifying records in a database, and altering them can lead to data integrity issues.
  Cause:
  
  Modification of Key Fields: The most common cause of this error is that the application is trying to change the value of a key field in a data entity. Key fields are defined in the data model and should not be modified after the record is created.
  Incorrect Data Binding: If the data binding in the UI is not set up correctly, it may lead to attempts to change key fields inadvertently.
  User Actions: Users may inadvertently try to edit fields that are defined as key fields in the underlying data model.
  
  Solution:
  
  Review the Data Model: Check the data model definition to identify which fields are designated as key fields. Ensure that these fields are not being modified in the application logic.
  Adjust UI Logic: If the UI allows users to edit key fields, modify the UI to prevent editing of these fields. This can be done by setting the fields to read-only or hiding them from the user interface.
  Data Binding: Ensure that the data binding in the UI is correctly set up to prevent changes to key fields. Use appropriate binding modes (e.g., two-way binding) that respect the immutability of key fields.
  Error Handling: Implement error handling in the application to catch this error and provide user-friendly messages or guidance on how to proceed without changing key fields.
  
  Related Information:
  
  SAP Fiori Elements: If you are using Fiori Elements, ensure that your annotations are correctly defined in the OData service to prevent key fields from being editable.
  OData Services: Review the OData service definition to ensure that key fields are marked correctly and that the service is configured to handle updates appropriately.
  SAP Notes: Check for any relevant SAP Notes or documentation that may provide additional insights or updates related to this error message.
  
  By following these steps, you should be able to resolve the /UI2/PAGE021 Key fields must not be changed error and ensure that your application behaves as expected without compromising data integrity.