How To Fix CNV_DMC_MC_EXCEPTION077 - Structure &1 is a lookup table; it cannot be mapped to a target structure

SAP Error Message - Details

• Message type: E = Error

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

• Message number: 077

• Message text: Structure &1 is a lookup table; it cannot be mapped to a target structure

A lookup table contains records that are looked up from a field in
another table to fill in the value of that field. The table can be
referenced by rules and used by mapping operations, but does not
directly provide content for fields in the target system.

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

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_EXCEPTION077 - Structure &1 is a lookup table; it cannot be mapped to a target structure ?

  The SAP error message CNV_DMC_MC_EXCEPTION077 indicates that there is an issue with mapping a lookup table to a target structure during a data migration or conversion process. This error typically arises in the context of using the SAP Data Migration Cockpit (DMC) or similar tools when trying to map data from a source system to a target system.
  Cause:
  The error occurs because:
  
  Lookup Table Definition: The source structure you are trying to map is defined as a lookup table, which means it is intended to provide reference data rather than being directly mapped to a target structure.
  Mapping Configuration: The mapping configuration may not be set up correctly, leading the system to attempt to map a lookup table directly to a target structure, which is not allowed.
  Data Model Mismatch: There may be a mismatch between the data model of the source and target systems, particularly regarding how lookup tables are handled.
  
  Solution:
  To resolve this error, you can take the following steps:
  
  
  Review Mapping Configuration:
  
  Check the mapping configuration in the DMC or the relevant migration tool. Ensure that the lookup table is not being directly mapped to a target structure.
  Instead, ensure that the lookup table is being used to populate fields in the target structure where necessary.
  
  
  
  Adjust Data Model:
  
  If the target structure requires data from the lookup table, consider creating a separate mapping for the lookup table to ensure that it is processed correctly.
  Ensure that the target structure is designed to accommodate the data from the lookup table appropriately.
  
  
  
  Consult Documentation:
  
  Refer to the SAP documentation for the Data Migration Cockpit or the specific migration tool you are using. There may be guidelines on how to handle lookup tables and their mappings.
  
  
  
  Test with Sample Data:
  
  If possible, test the mapping with a smaller set of sample data to identify where the issue arises. This can help isolate the problem and allow for easier troubleshooting.
  
  
  
  Seek Support:
  
  If the issue persists, consider reaching out to SAP support or consulting with an SAP expert who has experience with data migration projects. They may provide insights specific to your scenario.
  
  
  
  Related Information:
  
  SAP Data Migration Cockpit (DMC): A tool used for migrating data from legacy systems to SAP S/4HANA or other SAP systems.
  Lookup Tables: These are tables that provide reference data, often used to ensure data integrity and consistency during data migration.
  Data Mapping: The process of defining how data from the source system corresponds to the target system, including handling of different data structures.
  
  By following these steps, you should be able to address the CNV_DMC_MC_EXCEPTION077 error and successfully complete your data migration process.