How To Fix FDT_EXPRESSIONS639 - Deep structure is not supported as result of DB Lookup expression

SAP Error Message - Details

• Message type: E = Error

• Message class: FDT_EXPRESSIONS - Formula & Derivation Tool: Expressions

• Message number: 639

• Message text: Deep structure is not supported as result of DB Lookup expression

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message FDT_EXPRESSIONS639 - Deep structure is not supported as result of DB Lookup expression ?

  The SAP error message FDT_EXPRESSIONS639 indicates that a deep structure is not supported as the result of a database lookup expression in the context of SAP's Field-Based Data Transformation (FDT) or similar data processing scenarios. This error typically arises when you are trying to use a database lookup that returns a complex structure (like a nested or deep structure) instead of a flat structure.
  Cause:
  
  Deep Structure: The error occurs because the database lookup is returning a deep structure (a structure that contains nested tables or structures), which is not supported in the context of the expression you are trying to use.
  Expression Configuration: The configuration of the expression may be set up to expect a flat structure, but the lookup is returning a more complex data type.
  Data Model: The underlying data model may not be designed to handle deep structures in the context of the specific operation you are performing.
  
  Solution:
  
  Modify the Database Lookup: Adjust the database lookup to ensure that it returns a flat structure instead of a deep structure. This may involve changing the SQL query or the way the data is being retrieved.
  Use a Different Expression: If possible, use a different expression or transformation that can handle deep structures, or break down the deep structure into its components before using it in the lookup.
  Flatten the Structure: If you have control over the data model, consider flattening the structure in the database or in the transformation logic to ensure compatibility with the expected output.
  Check Documentation: Review the SAP documentation for the specific version you are using to understand the limitations and supported data types for database lookups and expressions.
  
  Related Information:
  
  SAP Notes: Check for any relevant SAP Notes that may address this specific error or provide additional guidance on handling deep structures in database lookups.
  FDT Documentation: Review the official SAP documentation for Field-Based Data Transformation (FDT) to understand the supported data types and structures.
  Community Forums: Engage with SAP community forums or support channels where similar issues may have been discussed, and solutions or workarounds may have been shared.
  
  By addressing the structure of the data being returned by the database lookup and ensuring compatibility with the expected output, you should be able to resolve the error FDT_EXPRESSIONS639.