How To Fix DT455 - Field &: String type is not allowed

SAP Error Message - Details

• Message type: E = Error

• Message class: DT - Table activation (incl. indexes)

• Message number: 455

• Message text: Field &: String type is not allowed

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message DT455 - Field &: String type is not allowed ?

  The SAP error message DT455, which states "Field &: String type is not allowed," typically occurs when there is an attempt to use a string data type in a context where it is not permitted. This can happen in various scenarios, such as when defining data types in ABAP programs, creating data elements, or working with structures and tables.
  Cause:
  
  Data Type Mismatch: The error usually arises when a field is defined with a string type (like STRING or XSTRING) in a context that requires a fixed-length character type (like CHAR, NUMC, etc.).
  Inappropriate Use of String: Certain operations or function modules may not support string types, leading to this error when they are used.
  Field Definition Issues: If a field in a structure or table is defined incorrectly, it can lead to this error when the program tries to access or manipulate that field.
  
  Solution:
  
  Check Field Definitions: Review the data definitions in your ABAP program or data dictionary. Ensure that fields expected to be of a fixed length are not defined as STRING.
  Change Data Types: If you find that a field is defined as STRING, consider changing it to a fixed-length type like CHAR or NUMC, depending on the intended use.
  Review Function Module/Method Calls: If the error occurs during a function module or method call, check the parameter types being passed. Ensure that you are not passing a string where a fixed-length type is expected.
  Use Appropriate Data Types: If you need to handle variable-length strings, consider using CHAR with a defined length or using CLOB for larger text data, depending on the context.
  
  Related Information:
  
  ABAP Data Types: Familiarize yourself with the different data types in ABAP and their appropriate use cases. The main types include CHAR, NUMC, DATS, TIMS, STRING, and XSTRING.
  SAP Documentation: Refer to the official SAP documentation for guidelines on data type usage and best practices in ABAP programming.
  Debugging: Use the ABAP debugger to trace the execution of your program and identify where the error is being triggered. This can help you pinpoint the exact field or operation causing the issue.
  
  By addressing the data type definitions and ensuring compatibility with the expected types in your SAP environment, you should be able to resolve the DT455 error.