How To Fix SADL_GW_DT_CDS044 - Statements of type 'union' are not allowed in consumption CDS view &1.

SAP Error Message - Details

• Message type: E = Error

• Message class: SADL_GW_DT_CDS - Messages CDS Checks

• Message number: 044

• Message text: Statements of type 'union' are not allowed in consumption CDS view &1.

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message SADL_GW_DT_CDS044 - Statements of type 'union' are not allowed in consumption CDS view &1. ?

  The error message SADL_GW_DT_CDS044 in SAP indicates that there is an issue with the definition of a Core Data Services (CDS) view, specifically that it contains a UNION statement, which is not allowed in consumption CDS views. This error typically arises when you are trying to create a CDS view that is intended to be consumed by OData services or other applications, and it includes a UNION operation.
  Cause
  The primary cause of this error is the use of a UNION operator in the definition of a CDS view that is meant for consumption. Consumption CDS views are designed to be simple and efficient for data retrieval, and the use of UNION complicates the data model, making it unsuitable for consumption scenarios.
  Solution
  To resolve this error, you can consider the following approaches:
  
  
  Refactor the CDS View:
  
  Instead of using a UNION, try to achieve the same result using other SQL constructs that are allowed in consumption CDS views. For example, you can use JOIN operations or create separate CDS views for each part of the data and then combine them at a higher level if necessary.
  
  
  
  Create a Non-Consumption CDS View:
  
  If the UNION operation is essential for your data model, consider creating a non-consumption CDS view (i.e., a CDS view that is not intended for OData consumption). This view can include the UNION and can be used as a base for other views.
  
  
  
  Use a Calculation View:
  
  If you are working with SAP HANA, you might consider using a calculation view instead of a CDS view. Calculation views can handle more complex scenarios, including UNION operations.
  
  
  
  Check for Alternative Data Models:
  
  Review your data model to see if there are alternative ways to structure your data that do not require a UNION. Sometimes, restructuring the underlying tables or views can eliminate the need for a UNION.
  
  
  
  Related Information
  
  CDS View Types: Understand the difference between consumption and non-consumption CDS views. Consumption views are optimized for OData services, while non-consumption views can include more complex SQL logic.
  SAP Documentation: Refer to the official SAP documentation on CDS views for best practices and guidelines on how to structure your views.
  Performance Considerations: Keep in mind that while UNION can be useful for combining datasets, it may have performance implications, especially in large datasets. Always consider the performance impact of your data model.
  
  By following these guidelines, you should be able to resolve the SADL_GW_DT_CDS044 error and create a valid CDS view that meets your requirements.