How To Fix GB309 - Expression with subfield of field & in table & not permitted.

SAP Error Message - Details

• Message type: E = Error

• Message class: GB - Messages used by the Boolean code generator

• Message number: 309

• Message text: Expression with subfield of field & in table & not permitted.

What causes this issue?

You used a field for which a conversion routine is stored.

System Response

Processing is terminated.

How to fix this error?

Work with a user exit that calls up the conversion routine. In this
exit, you can use offset and length to manipulate parts of the external
representation of the field. (The external representation is the form
in which the field contents appear on the screen.)

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message GB309 - Expression with subfield of field & in table & not permitted. ?

  The SAP error message GB309 indicates that there is an issue with the use of subfields in a field within a specific table. This error typically arises when you are trying to access or manipulate a subfield of a field in a way that is not permitted by the system's data structure or rules.
  Cause:
  
  Subfield Access: The error occurs when you attempt to access a subfield of a field that is not allowed in the context of the operation you are performing. This can happen in various scenarios, such as during data processing, report generation, or when writing custom ABAP code.
  Data Structure: The underlying data structure of the table may not support subfield access for the specified field. This can be due to the field being defined as a simple data type rather than a structured type.
  Incorrect Syntax: There may be a syntax error in the code where the subfield is being referenced incorrectly.
  
  Solution:
  
  Check Field Definition: Review the definition of the field in the relevant table to ensure that it is indeed a structured field that supports subfields. If it is a simple field, you cannot access subfields.
  Correct Syntax: If you are writing ABAP code, ensure that you are using the correct syntax for accessing fields and subfields. For example, if you are trying to access a subfield, make sure you are using the correct notation.
  Use Alternative Logic: If the field does not support subfields, consider using alternative logic to achieve your goal. This may involve using the entire field instead of trying to access a subfield.
  Debugging: If you are unsure where the error is occurring, use the debugging tools in SAP to trace the execution of your code and identify the exact point where the error is triggered.
  
  Related Information:
  
  SAP Documentation: Refer to the SAP Help Portal or the specific documentation for the module you are working with to understand the data structures and field definitions.
  ABAP Development: If you are working with ABAP, familiarize yourself with the data types and structures in ABAP programming to avoid such errors in the future.
  Community Forums: Check SAP community forums or discussion boards for similar issues and solutions shared by other users.
  
  If the problem persists after checking these aspects, consider reaching out to your SAP support team or consulting with an SAP expert for further assistance.