How To Fix CNV256 - For table &, field &, routine & source package is not unique

SAP Error Message - Details

• Message type: E = Error

• Message class: CNV - Conversion: Messages for Conversion Services (CNCC)

• Message number: 256

• Message text: For table &, field &, routine & source package is not unique

What causes this issue?

The combination
table name &V1&
field name &V2&
routine &V3&
occurs in more than one source package. This causes a conflict.

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?

Set field the source package manually

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message CNV256 - For table &, field &, routine & source package is not unique ?

  The SAP error message CNV256 typically indicates that there is a problem with the data conversion process, specifically related to the uniqueness of a source package in a data migration or conversion scenario. This error often arises during the execution of a data migration project, particularly when using SAP's data migration tools or during the execution of a custom program.
  Cause:
  The error message "For table &, field &, routine & source package is not unique" suggests that there is a conflict or ambiguity in the data being processed. This can occur due to several reasons:
  
  
  Duplicate Entries: There may be duplicate entries in the source data for the specified table and field, which makes it impossible for the system to determine which entry to use.
  
  
  Incorrect Mapping: The mapping of fields from the source to the target may not be correctly defined, leading to multiple potential matches.
  
  
  Data Integrity Issues: There may be issues with the integrity of the data in the source system, such as missing or inconsistent values.
  
  
  Configuration Errors: The configuration of the data migration tool or the routines being used may not be set up correctly, leading to conflicts.
  
  
  Solution:
  To resolve the CNV256 error, you can take the following steps:
  
  
  Check for Duplicates: Review the source data for the specified table and field to identify any duplicate entries. You can use SQL queries or data analysis tools to find duplicates.
  
  
  Review Mapping: Ensure that the mapping of fields from the source to the target is correctly defined. Make sure that each source field maps to a unique target field.
  
  
  Data Cleansing: Cleanse the source data to remove duplicates and ensure data integrity. This may involve deduplication processes or correcting inconsistent values.
  
  
  Configuration Review: Check the configuration of the data migration tool or routines being used. Ensure that they are set up correctly and that there are no conflicting settings.
  
  
  Debugging: If you have access to the code or routines being executed, consider debugging the process to identify where the conflict is occurring.
  
  
  Consult Documentation: Refer to SAP documentation or notes related to the specific data migration tool you are using for any additional guidance or known issues.
  
  
  Seek Support: If the issue persists, consider reaching out to SAP support or consulting with an SAP expert who can provide more tailored assistance based on your specific scenario.
  
  
  Related Information:
  
  SAP Notes: Check for any relevant SAP Notes that may address this specific error or provide additional troubleshooting steps.
  Data Migration Tools: Familiarize yourself with the specific data migration tools being used (e.g., SAP S/4HANA Migration Cockpit, SAP Data Services) and their documentation for best practices.
  Testing: After making changes, conduct thorough testing to ensure that the data migration process works as expected without further errors.
  
  By following these steps, you should be able to identify and resolve the cause of the CNV256 error in your SAP environment.