Gavin King ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *created* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiNGEyOTM3N2Fi... ) / Bug ( https://hibernate.atlassian.net/browse/HHH-16464?atlOrigin=eyJpIjoiNGEyOT... ) HHH-16464 ( https://hibernate.atlassian.net/browse/HHH-16464?atlOrigin=eyJpIjoiNGEyOT... ) Foreign key constraint not created for @OneToOne mapping with missing @MapsId ( https://hibernate.atlassian.net/browse/HHH-16464?atlOrigin=eyJpIjoiNGEyOT... ) Issue Type: Bug Assignee: Unassigned Components: hibernate-core Created: 12/Apr/2023 04:23 AM Priority: Major Reporter: Gavin King ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) Given the following mapping: @OneToOne @JoinColumn(name = "id" ) private User user; No foreign key constraint is created. The fix is to add a @MapsId annotation, but this is not obvious at all. Since we don’t reject this mapping, we should create the correct FK constraint even when @MapsId is missing. ( https://hibernate.atlassian.net/browse/HHH-16464#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16464#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#100221- sha1:c4871f2 )