How To Fix 42689 - Different keys are not allowed for the same class

SAP Error Message - Details

• Message type: E = Error

• Message class: 42 - Information Workbench

• Message number: 689

• Message text: Different keys are not allowed for the same class

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message 42689 - Different keys are not allowed for the same class ?

  The SAP error message 42689, which states "Different keys are not allowed for the same class," typically occurs in the context of class-based object-oriented programming in SAP, particularly when dealing with class definitions and their instances.
  Cause:
  This error usually arises when there is an attempt to create or manipulate instances of a class that have conflicting keys. In SAP, classes can have attributes that serve as keys, and if two instances of the same class are defined with different keys, the system will throw this error. This can happen in various scenarios, such as:
  
  Inconsistent Key Definitions: When a class is defined with a certain key, and later an attempt is made to create another instance of the same class with a different key definition.
  Inheritance Issues: If a subclass is trying to redefine keys that are already defined in the parent class.
  Data Dictionary Issues: When working with database tables or structures that are linked to classes, inconsistencies in key definitions can lead to this error.
  
  Solution:
  To resolve this error, you can take the following steps:
  
  
  Check Class Definitions: Review the class definitions to ensure that all instances of the class are using the same key. If you need to change the key, you may need to redefine the class or create a new class altogether.
  
  
  Review Inheritance: If you are using inheritance, ensure that the subclass does not redefine keys that are already defined in the parent class. If necessary, adjust the subclass to align with the parent class's key definitions.
  
  
  Data Dictionary Consistency: If the class is linked to a database table or structure, ensure that the keys in the data dictionary are consistent with the class definition. You may need to adjust the database structure or the class definition accordingly.
  
  
  Debugging: Use debugging tools in SAP to trace where the error is being triggered. This can help you identify the specific instance or operation that is causing the conflict.
  
  
  Consult Documentation: Refer to SAP documentation or community forums for additional insights or similar cases that may provide a solution.
  
  
  Related Information:
  
  SAP Notes: Check SAP Notes for any known issues or patches related to this error message.
  SAP Community: Engage with the SAP Community forums to see if other users have encountered and resolved similar issues.
  ABAP Development: If you are working with ABAP, ensure that your coding practices align with SAP's object-oriented programming guidelines.
  
  By following these steps, you should be able to identify the root cause of the error and implement a suitable solution.