Steve Ebersole ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *commented* on HHH-16019 ( https://hibernate.atlassian.net/browse/HHH-16019?atlOrigin=eyJpIjoiMjEyYj... ) Re: @Where not applied across association boundaries ( https://hibernate.atlassian.net/browse/HHH-16019?atlOrigin=eyJpIjoiMjEyYj... ) We did in fact change the behavior ( https://docs.jboss.org/hibernate/orm/6.0/migration-guide/migration-guide.... ) such that a unique constraint is always added for a 1-1 mapping. That was actually a bug in previous releases. But as as you can see from the link, that was actually changed in 6.0. Perhaps an additional condition was recognized later and addressed. But regardless, hopefully you can understand that a 1-1 mapping would more-than-correctly have unique constraints defined. ( https://hibernate.atlassian.net/browse/HHH-16019#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16019#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#100217- sha1:077879e )