Marco Belladelli ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=637b480... ) *created* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiZGYyNmRhOTEx... ) / Improvement ( https://hibernate.atlassian.net/browse/HHH-16761?atlOrigin=eyJpIjoiZGYyNm... ) HHH-16761 ( https://hibernate.atlassian.net/browse/HHH-16761?atlOrigin=eyJpIjoiZGYyNm... ) Throw an appropriate error when an entity defines more @Id fields than its @IdClass ( https://hibernate.atlassian.net/browse/HHH-16761?atlOrigin=eyJpIjoiZGYyNm... ) Issue Type: Improvement Affects Versions: 6.2.4 Assignee: Marco Belladelli ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=637b480... ) Created: 07/Jun/2023 02:10 AM Priority: Major Reporter: Marco Belladelli ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=637b480... ) Currently we have a validation that checks that all fields of an @IdClass are included in the corresponding entity class as @Id annotated properties. We do not, however, check if there are more @Id annotated fields in the entity than what we expect, and this causes unexpected behavior (i.e. the additional @Id field might “override” the @IdClass and be set as simple-valued identifier for the entity class). For example: public static class PK { private Long id; private String username; } @Entity @IdClass( PK.class ) public static class User { @Id private Long id; @Id private String username; @Id private Integer anotherId; } This should be considered a wrong mapping, and an appropriate error should be thrown. ( https://hibernate.atlassian.net/browse/HHH-16761#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16761#add-comment?atlOrigin=ey... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100225- sha1:62413c2 )