How To Fix CFD_REGISTRY_CHECK023 - Extension Include View &1 must select from exactly one data source

SAP Error Message - Details

• Message type: E = Error

• Message class: CFD_REGISTRY_CHECK - Custom Fields: Messages for Registry Check

• Message number: 023

• Message text: Extension Include View &1 must select from exactly one data source

Self-Explanatory Message

Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.

To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.

Unfortunately, there isn't any extra information in this error notice.

What else can you do?

First, use our AnswerBot below to get a possible cause and solution (requires a premium subscription).

Also, review the in-depth Common Questions & Answers listed below; you could discover a solution there or be able to connect with others who have faced similar challenges.

You can also try searching the SAP support portal (support.sap.com) but you need a special user ID to access it. It is possible that an SAP support note exists that provides additional details about the mistake or even steps for fixing it.

Smart SAP Assistant

• What is the cause and solution for SAP error message CFD_REGISTRY_CHECK023 - Extension Include View &1 must select from exactly one data source ?

  The SAP error message CFD_REGISTRY_CHECK023, which states "Extension Include View &1 must select from exactly one data source," typically occurs in the context of SAP's Core Data Services (CDS) views or when working with extension include views in the ABAP environment. This error indicates that the specified view is attempting to select data from multiple sources, which is not allowed for extension include views.
  Cause:
  
  Multiple Data Sources: The extension include view is defined to select from more than one data source (e.g., multiple tables or views), which violates the requirement that it must select from exactly one data source.
  Incorrect View Definition: The view might be incorrectly defined in the ABAP Dictionary or in the CDS view definition, leading to ambiguity in the data source selection.
  Inconsistent Data Model: The underlying data model may not be properly aligned, causing the extension include view to inadvertently reference multiple sources.
  
  Solution:
  
  
  Review the View Definition: Check the definition of the extension include view. Ensure that it is selecting from exactly one data source. If it is currently selecting from multiple sources, you will need to refactor the view to comply with this requirement.
  
  
  Modify the SQL Query: If you are using a SQL query in the view, ensure that the FROM clause specifies only one table or view. If you need to join data from multiple sources, consider creating a separate view that handles the joins and then use that view as the data source for your extension include view.
  
  
  Check for Inheritance: If the extension include view is meant to extend another view, ensure that the base view is correctly defined and that the extension is properly inheriting from it.
  
  
  Use a Composite View: If you need to combine data from multiple sources, consider creating a composite view that aggregates the necessary data and then use that composite view as the single data source for your extension include view.
  
  
  Testing: After making the necessary changes, activate the view and test it to ensure that the error is resolved.
  
  
  Related Information:
  
  SAP Documentation: Refer to the official SAP documentation on Core Data Services (CDS) and extension include views for detailed guidelines on how to define and use these constructs.
  ABAP Development Tools: Utilize the ABAP Development Tools (ADT) in Eclipse for better visibility and management of your views, including syntax checks and error highlighting.
  SAP Community: Engage with the SAP Community forums for insights and solutions from other developers who may have encountered similar issues.
  
  By following these steps, you should be able to resolve the CFD_REGISTRY_CHECK023 error and ensure that your extension include view is correctly defined.