How To Fix ESH_CDS_VAL002 - DDL &1 contains UNION

SAP Error Message - Details

• Message type: E = Error

• Message class: ESH_CDS_VAL -

• Message number: 002

• Message text: DDL &1 contains UNION

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message ESH_CDS_VAL002 - DDL &1 contains UNION ?

  The SAP error message ESH_CDS_VAL002 indicates that there is an issue with a Core Data Services (CDS) view that contains a UNION operation. This error typically arises when the system is trying to validate or activate a CDS view that includes a UNION clause, which is not supported in certain contexts or configurations.
  Cause:
  
  Unsupported SQL Constructs: The use of UNION in a CDS view may not be supported in the context where the view is being used, such as in certain types of analytical queries or when trying to expose the view as a service.
  Incompatibility with Consumption: The CDS view might be intended for consumption in a way that does not support UNION, such as in OData services or when used in certain reporting tools.
  Database Compatibility: The underlying database may not support the specific SQL syntax or constructs used in the CDS view.
  
  Solution:
  
  Refactor the CDS View: If possible, refactor the CDS view to avoid using UNION. Instead, consider using JOIN operations or creating separate views that can be combined at a higher level.
  Check for Compatibility: Ensure that the CDS view is compatible with the intended use case. If it is meant to be exposed as an OData service, check the documentation for any restrictions on SQL constructs.
  Use Alternative Approaches: If you need to combine data from multiple sources, consider using other methods such as creating separate views and then combining them in the application layer or using a different approach to aggregate the data.
  Consult Documentation: Review the SAP documentation for Core Data Services to understand the limitations and best practices for creating CDS views, especially regarding the use of UNION.
  
  Related Information:
  
  SAP Notes: Check for any relevant SAP Notes that might address this specific error or provide guidance on best practices for CDS views.
  SAP Community: Engage with the SAP Community forums to see if other users have encountered similar issues and what solutions they have found.
  CDS View Documentation: Familiarize yourself with the official SAP documentation on CDS views, which provides guidelines on supported SQL constructs and best practices for designing views.
  
  By addressing the underlying cause of the error and considering alternative approaches, you can resolve the issue and successfully activate or validate your CDS view.