How To Fix CNV_DMC_MC_EXCEPTION198 - Cannot change length of fixed value; see long text

SAP Error Message - Details

• Message type: E = Error

• Message class: CNV_DMC_MC_EXCEPTION - Exception texts of Migration Object Modeller

• Message number: 198

• Message text: Cannot change length of fixed value; see long text

What causes this issue?

You want to change the length of the fixed value. However, the default
fixed value is longer than the new length. Changing the length of the
fixed value would therefore result in data loss and is not permitted.

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_DMC_MC_EXCEPTION198 - Cannot change length of fixed value; see long text ?

  The SAP error message CNV_DMC_MC_EXCEPTION198 typically occurs during data migration processes, particularly when using the SAP Data Migration Cockpit (DMC) or similar tools. This error indicates that there is an attempt to change the length of a fixed value field, which is not allowed.
  Cause:
  
  Fixed Length Fields: The error arises when there is an attempt to modify the length of a field that is defined as a fixed length in the target structure. This can happen if the source data has a different length than what is defined in the target system.
  Data Mapping Issues: There may be discrepancies in the data mapping configuration where the source and target field lengths do not match.
  Data Type Mismatch: The data type of the source field may not be compatible with the target field, leading to issues when trying to migrate the data.
  
  Solution:
  
  Check Field Definitions: Review the field definitions in both the source and target systems to ensure that the lengths and data types match. If the target field is defined as fixed length, ensure that the source data conforms to this length.
  Adjust Data Mapping: If you are using a mapping tool, check the mapping configuration to ensure that the source fields are correctly mapped to the target fields. Adjust the mapping if necessary to ensure compatibility.
  Data Transformation: If the source data cannot be changed, consider applying transformations to the data during the migration process to ensure that it fits the target structure. This may involve truncating or padding the data to meet the fixed length requirements.
  Consult Long Text: The error message suggests checking the long text for more details. In SAP, you can usually find additional information about the error by looking at the long text associated with the error message. This may provide specific guidance on how to resolve the issue.
  
  Related Information:
  
  SAP Notes: Check for any relevant SAP Notes that may address this specific error or provide additional guidance on data migration issues.
  Documentation: Review the SAP Data Migration Cockpit documentation for best practices and guidelines on data migration, including field mapping and data transformation techniques.
  Testing: Before performing a full migration, conduct tests with a smaller dataset to identify and resolve any issues without impacting the entire migration process.
  
  If the problem persists after following these steps, consider reaching out to SAP support or consulting with an SAP expert who specializes in data migration.