Message type: E = Error
Message class:  SADL_GW_DT_CDS - Messages CDS Checks 
Message number: 029
Message text: CDS view &1 cannot be draft-enabled due to underlying transactional view.
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The SAP error message SADL_GW_DT_CDS029 indicates that a Core Data Services (CDS) view cannot be draft-enabled because it is based on an underlying transactional view that does not support draft functionality. This typically occurs in the context of SAP Fiori applications that utilize draft handling for data persistence.
Cause: The error arises when you attempt to enable draft functionality for a CDS view that is based on a transactional view (or a view that does not support draft capabilities). Draft handling in SAP is designed to work with specific types of data models, and if the underlying data source does not support this feature, the draft functionality cannot be enabled.
Solution: To resolve this issue, consider the following steps: Check the Underlying View: Review the underlying transactional view that your CDS view is based on. Ensure that it is designed to support draft functionality. If it is not, you may need to create a new
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