How To Fix TR156 - Key contains field with a special data type

SAP Error Message - Details

• Message type: E = Error

• Message class: TR - Change and Transport System

• Message number: 156

• Message text: Key contains field with a special data type

What causes this issue?

The key of the selected table contains one or more fields which do not
have the data type character or numeric.

System Response

An entry cannot be made in these special fields.

How to fix this error?

Enter a generic key.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message TR156 - Key contains field with a special data type ?

  The SAP error message TR156, which states "Key contains field with a special data type," typically occurs when you are trying to create or modify a table or a data structure in SAP that includes a key field with a data type that is not supported for key fields. This can happen in various contexts, such as when defining database tables, structures, or views in the Data Dictionary (SE11).
  Cause:
  The error is usually caused by one of the following reasons:
  
  Unsupported Data Types: The key field is defined with a data type that cannot be used as a key. For example, certain complex data types or reference types may not be allowed.
  Field Length Issues: The length of the key field may exceed the maximum allowed length for key fields.
  Non-primitive Data Types: Using non-primitive data types (like structures or tables) as key fields is not permitted.
  
  Solution:
  To resolve the TR156 error, you can take the following steps:
  
  
  Check Data Types: Review the data types of the fields that you are trying to use as keys. Ensure that they are primitive data types (e.g., CHAR, NUMC, INT, etc.) that are allowed as key fields.
  
  
  Modify Key Fields: If you find that a key field is using a special or unsupported data type, consider changing it to a supported data type. For example, if you are using a structure or a reference type, replace it with a simple data type.
  
  
  Adjust Field Length: Ensure that the length of the key fields does not exceed the maximum allowed length for key fields in SAP.
  
  
  Review Table/Structure Definition: If you are working with a custom table or structure, double-check the entire definition to ensure that all key fields are correctly defined.
  
  
  Consult Documentation: Refer to SAP documentation or the Data Dictionary documentation for specific guidelines on key field definitions and supported data types.
  
  
  Related Information:
  
  Transaction Codes: You can use transaction codes like SE11 (Data Dictionary), SE14 (Database Utility), and SE80 (Object Navigator) to manage and troubleshoot database objects.
  SAP Notes: Check SAP Notes for any known issues or additional guidance related to this error message.
  Community Forums: SAP Community and other forums can be helpful for finding similar issues faced by other users and their solutions.
  
  By following these steps, you should be able to identify the cause of the TR156 error and implement the necessary changes to resolve it.