How To Fix DT454 - Field &: Preceding & field cannot be a key field

SAP Error Message - Details

• Message type: E = Error

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

• Message number: 454

• Message text: Field &: Preceding & field cannot be a key field

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message DT454 - Field &: Preceding & field cannot be a key field ?

  The SAP error message DT454 ("Field &: Preceding & field cannot be a key field") typically occurs in the context of data dictionary definitions, particularly when defining database tables or structures in the ABAP Dictionary (SE11). This error indicates that there is an issue with the key fields defined for a table or structure.
  Cause:
  The error arises when you attempt to define a field as a key field that is not allowed to be a key field based on its position or the context of the preceding field. This can happen due to several reasons:
  
  Field Positioning: The field you are trying to set as a key field is positioned after another field that is already defined as a key field, which is not allowed.
  Data Type Restrictions: Certain data types or field attributes may not be allowed as key fields.
  Table Structure: The overall structure of the table may not support the key field definition due to existing constraints or relationships.
  
  Solution:
  To resolve the DT454 error, you can take the following steps:
  
  
  Check Field Order: Ensure that the field you are trying to define as a key field is positioned correctly in relation to other key fields. Key fields should be defined in a logical order.
  
  
  Review Field Attributes: Verify the attributes of the field you are trying to set as a key field. Ensure that it meets the requirements for being a key field (e.g., it should not be a calculated field or have certain incompatible data types).
  
  
  Modify Key Field Definition: If necessary, adjust the key field definitions. You may need to remove or change the key field status of other fields to accommodate the new key field.
  
  
  Consult Documentation: Refer to SAP documentation or the ABAP Dictionary documentation for specific rules regarding key field definitions.
  
  
  Test Changes: After making adjustments, activate the table or structure and check if the error persists.
  
  
  Related Information:
  
  Transaction Codes: You can use transaction codes SE11 (Data Dictionary) to view and modify table definitions.
  Field Types: Familiarize yourself with the different field types and their properties in SAP, as certain types may have restrictions on being used as key fields.
  SAP Notes: Check for any relevant SAP Notes that may address specific issues related to key field definitions or provide additional guidance.
  
  If the problem persists after following these steps, consider reaching out to your SAP Basis or ABAP development team for further assistance.