Message type: E = Error
Message class:  SADL_GW_DT_CDS - Messages CDS Checks 
Message number: 033
Message text: Key field &1 must not be annotated as &2.
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.
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.
The SAP error message SADL_GW_DT_CDS033 indicates that there is an issue with the annotations of a key field in a Core Data Services (CDS) view. Specifically, the error states that a key field (denoted by &1) must not be annotated as a certain type (denoted by &2). This typically occurs when the key field is incorrectly annotated in the CDS definition.
Cause: The error is usually caused by one of the following: Incorrect Annotations: A key field in the CDS view is annotated with an inappropriate annotation type. For example, a key field should not be annotated as @Aggregation or @UI if it is meant to be a key. Modeling Errors: There may be a misunderstanding in the data model where a field that is defined as a key is being treated as a non-key field or vice versa. Incompatibility with OData: If the CDS view is intended to be exposed as an OData service,
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
SADL_GW_DT_CDS032 Element &1 has inherited the annotation &2 and cannot be exposed.
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
SADL_GW_DT_CDS031 CDS view &1: Association to child &2 is missing.
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
SADL_GW_DT_CDS034 Element &1 cannot be used in annotation &2 because of annotation &3.
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
SADL_GW_DT_CDS035 Annotation '&1: &2' must not be used here.
What causes this issue?  The annotation <(>&<)>1 with the value <(>&<)>2 is used in a non-analytical CDS view, which i...
Click on this link to search all SAP messages.