How To Fix SD_CDS_ENTITY106 - Annotation &1 should only be used once within a select list.

SAP Error Message - Details

• Message type: E = Error

• Message class: SD_CDS_ENTITY - Messages for STOBS/entities

• Message number: 106

• Message text: Annotation &1 should only be used once within a select list.

What causes this issue?

The following annotations should be used only once within the select or
element list of CDS objects:
@Semantics.currencyCode
@Semantics.unitOfMeasure
Elements having these annotations assigned are used as default
references for calculated elements of data type CURR/QUAN. In case of
multiple assignments it is not defined which of the elements is used as
reference.
In order to avoid this warning it is also possible to assign the
following annotations to all CURR-/QUAN-typed elements:
@Semantics.amount.currencyCode
@Semantics.quantity.unitOfMeasure

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message SD_CDS_ENTITY106 - Annotation &1 should only be used once within a select list. ?

  The SAP error message SD_CDS_ENTITY106 indicates that there is an issue with the way annotations are being used in a Core Data Services (CDS) view. Specifically, the error message states that a particular annotation (denoted by &1) is being used more than once in the select list of the CDS view, which is not allowed.
  Cause:
  The error occurs when:
  
  An annotation is defined multiple times in the select list of a CDS view.
  Annotations are meant to provide metadata about the fields in the CDS view, and each annotation should be unique for each field.
  
  Solution:
  To resolve this error, you should:
  
  Review the CDS View Definition: Check the select list of your CDS view to identify where the annotation is being used multiple times.
  Remove Duplicate Annotations: Ensure that each annotation is only applied once. If you find duplicates, remove the extra instances.
  Consolidate Annotations: If you need to apply similar metadata to multiple fields, consider whether you can consolidate the annotations or apply them in a different way that adheres to the rules of CDS views.
  
  Example:
  If your CDS view looks something like this:
  define view Z_MY_CDS_VIEW
  as select from my_table
  {
      key field1,
      field2 @Annotation1: 'value1',
      field3 @Annotation1: 'value2'  // This will cause the error
  }
  You would need to change it to:
  define view Z_MY_CDS_VIEW
  as select from my_table
  {
      key field1,
      field2 @Annotation1: 'value1',
      field3 @Annotation2: 'value2'  // Use a different annotation
  }
  Related Information:
  
  CDS Annotations: Familiarize yourself with the different types of annotations available in CDS views and their intended use.
  SAP Documentation: Refer to the official SAP documentation for Core Data Services to understand the rules and best practices for defining CDS views and using annotations.
  Debugging Tools: Use tools like the ABAP Development Tools (ADT) in Eclipse to help identify and correct issues in your CDS view definitions.
  
  By following these steps, you should be able to resolve the SD_CDS_ENTITY106 error and ensure that your CDS view is correctly defined.