Burkhard Graves ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *updated* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiNzNhOTExMmIx... ) / Bug ( https://hibernate.atlassian.net/browse/HHH-15591?atlOrigin=eyJpIjoiNzNhOT... ) HHH-15591 ( https://hibernate.atlassian.net/browse/HHH-15591?atlOrigin=eyJpIjoiNzNhOT... ) Unidirectional @OneToMany with @OrderColumn still throwing ConstraintViolationException (unique index violation) ( https://hibernate.atlassian.net/browse/HHH-15591?atlOrigin=eyJpIjoiNzNhOT... ) Change By: Burkhard Graves ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) There are several tickets dealing with this setup, see linked issues. What seems to work: * Adding one or more elements to the list * Removing one or more elements from the list What still does not work: * Swapping elements in the list * Simultaneously adding and removing elements from the list I added a PR which adds to two tests to {{UnidirectionalOneToManyOrderColumnTest}}, namely {code:java} @Test public void testSwapElementsAtZeroAndOne(EntityManagerFactoryScope scope) { long parentId = scope.fromTransaction( entityManager -> { ParentData parent = new ParentData(); entityManager.persist( parent ); String[] childrenStr = new String[] {"One", "Two"}; for ( String str : childrenStr ) { ChildData child = new ChildData( str ); entityManager.persist( child ); parent.getChildren().add( child ); } entityManager.flush(); List<ChildData> children = parent.getChildren(); ChildData child0 = children.get( 0 ); ChildData child1 = children.get( 1 ); children.set(0, child1); children.set(1, child0); return parent.id; } ); // if the above works, then test on {"Two", "One"} } @Test public void testAddAtZeroDeleteAtTwo(EntityManagerFactoryScope scope) { long parentId = scope.fromTransaction( entityManager -> { ParentData parent = new ParentData(); entityManager.persist( parent ); String[] childrenStr = new String[] {"One", "Two"}; for ( String str : childrenStr ) { ChildData child = new ChildData( str ); entityManager.persist( child ); parent.getChildren().add( child ); } entityManager.flush(); List<ChildData> children = parent.getChildren(); children.add( 0, new ChildData( "Zero" ) ); children.remove( 2 ); return parent.id; } ); // if the above works, then test on {"Zero", "One"} }{code} Both tests fail (in h2 and presumably many other databases). ( https://hibernate.atlassian.net/browse/HHH-15591#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-15591#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#100207- sha1:591c2ef )