How To Fix CNV_PE_GEN120 - Unable to generate DDIC structure &1 - field names not allowed

SAP Error Message - Details

• Message type: E = Error

• Message class: CNV_PE_GEN - Messages for object generation

• Message number: 120

• Message text: Unable to generate DDIC structure &1 - field names not allowed

What causes this issue?

Generation of DDIC structure &V1& is not possible. At least one of its
fields has name &V2& that is not allowed.

System Response

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

How to fix this error?

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 CNV_PE_GEN120 - Unable to generate DDIC structure &1 - field names not allowed ?

  The SAP error message CNV_PE_GEN120 indicates that there is an issue with generating a Data Dictionary (DDIC) structure due to the presence of field names that are not allowed. This error typically occurs during data migration or conversion processes, particularly when using SAP's tools for data transfer or transformation.
  Cause:
  The error is usually caused by one or more of the following reasons:
  
  
  Invalid Field Names: The field names in the structure you are trying to generate may contain invalid characters or may not conform to SAP naming conventions. For example, field names should not start with a number, should not contain special characters (except for underscores), and should not exceed the maximum length.
  
  
  Reserved Keywords: The field names may be using reserved keywords or names that are already used by SAP or other objects in the system.
  
  
  Data Type Issues: There may be inconsistencies in the data types defined for the fields, which can lead to issues when generating the DDIC structure.
  
  
  Configuration Issues: There may be issues with the configuration of the data migration tool or the specific settings used for the conversion process.
  
  
  Solution:
  To resolve the CNV_PE_GEN120 error, you can take the following steps:
  
  
  Check Field Names: Review the field names in the structure you are trying to generate. Ensure that they adhere to SAP naming conventions:
  
  Must start with a letter.
  Can only contain letters, numbers, and underscores.
  Should not exceed 30 characters in length.
  
  
  
  Avoid Reserved Keywords: Make sure that none of the field names are reserved keywords in SAP. You can refer to SAP documentation or the ABAP Dictionary for a list of reserved keywords.
  
  
  Review Data Types: Ensure that the data types for the fields are correctly defined and compatible with the DDIC structure you are trying to create.
  
  
  Adjust Configuration: If you are using a specific data migration tool (like SAP S/4HANA Migration Cockpit or SAP Data Services), check the configuration settings to ensure they are set up correctly.
  
  
  Consult Documentation: Refer to the SAP documentation related to the specific migration or conversion tool you are using for any additional guidelines or restrictions.
  
  
  Testing: After making the necessary changes, attempt to regenerate the DDIC structure to see if the error persists.
  
  
  Related Information:
  
  SAP Notes: Check for any relevant SAP Notes that may address this specific error or provide additional troubleshooting steps.
  SAP Community: Engage with the SAP Community forums to see if other users have encountered similar issues and what solutions they found effective.
  Documentation: Review the official SAP documentation for the data migration tool you are using, as it may contain specific guidelines for naming conventions and structure generation.
  
  By following these steps, you should be able to identify and resolve the cause of the CNV_PE_GEN120 error in your SAP environment.