How To Fix CSP_BDEF_CHECK019 - CDS view '&1' must not be built on a JOIN

SAP Error Message - Details

• Message type: E = Error

• Message class: CSP_BDEF_CHECK - Messages for CSP-implemented BDEF checks

• Message number: 019

• Message text: CDS view '&1' must not be built on a JOIN

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message CSP_BDEF_CHECK019 - CDS view '&1' must not be built on a JOIN ?

  The SAP error message CSP_BDEF_CHECK019 indicates that a Core Data Services (CDS) view is being defined in a way that is not allowed by the system. Specifically, it states that the CDS view '&1' must not be built on a JOIN. This error typically arises when you attempt to create a CDS view that uses a JOIN operation, which is not permitted in certain contexts, particularly when the view is intended for specific types of consumption or when it is being used in a certain way (e.g., for analytical purposes).
  Cause:
  
  CDS View Definition: The CDS view is defined using a JOIN between two or more database tables or views, which is not allowed in the context where the view is being used.
  Restrictions on CDS Views: Certain types of CDS views, especially those intended for use in specific applications or frameworks (like SAP Fiori or SAP BW), may have restrictions that prevent the use of JOINs.
  Incompatibility with Consumption: The view may be intended for consumption in a way that requires a flat structure, which cannot be achieved with JOINs.
  
  Solution:
  
  
  Refactor the CDS View: Modify the CDS view definition to eliminate the JOIN. This can be done by:
  
  Using associations instead of JOINs. Associations allow you to define relationships between entities without physically joining them in the SQL query.
  Creating separate CDS views for each entity and then using them in a way that does not require a JOIN.
  Flattening the data model if possible, to avoid the need for JOINs.
  
  
  
  Check the Context: Ensure that the CDS view is being created in the correct context. If it is meant for analytical purposes, consider using a different approach that aligns with the requirements of the analytical framework.
  
  
  Review Documentation: Consult the SAP documentation for CDS views to understand the specific restrictions and best practices for creating views that are intended for your use case.
  
  
  Testing: After making changes, test the CDS view to ensure that it meets the functional requirements and does not produce any further errors.
  
  
  Related Information:
  
  Associations vs. Joins: Understand the difference between associations and joins in CDS views. Associations are a way to define relationships between entities without physically joining them, which can help avoid this error.
  SAP Notes and Community: Check SAP Notes or the SAP Community for any updates or similar issues reported by other users. There may be specific notes addressing this error or providing additional guidance.
  Performance Considerations: Be aware that while associations can help avoid this error, they may have performance implications depending on how they are used in the application.
  
  By following these steps, you should be able to resolve the CSP_BDEF_CHECK019 error and successfully create your CDS view without using JOINs.