Nara Simha ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=63f1102... ) *updated* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiMjU2NTZlYzQy... ) / Bug ( https://hibernate.atlassian.net/browse/HHH-16502?atlOrigin=eyJpIjoiMjU2NT... ) HHH-16502 ( https://hibernate.atlassian.net/browse/HHH-16502?atlOrigin=eyJpIjoiMjU2NT... ) Hib5: @OneToOne mapping with unique=true throws "caused a duplicate key value in a unique or primary key constraint' ( https://hibernate.atlassian.net/browse/HHH-16502?atlOrigin=eyJpIjoiMjU2NT... ) Change By: Nara Simha ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=63f1102... ) The following mapping works fine in Hib 3.x {noformat}@OneToOne(fetch = FetchType.LAZY, cascade = { CascadeType.ALL }, optional = true) @JoinColumn(name = PAYLOAD_FILTER_COLUMN "PAYLOAD_FILTER" , unique = true) private PayloadFilterExpression payloadFilter;{noformat} !dampen-20230424-054645 (7efd1ac9-095c-4083-a638-335bedcd1efd).png|width=1667,height=937! +*_The same mapping throws the following error in Hib 5.x_*+ {noformat}This table, NMS_DAMPEN_CONFIG has a one-to-one relationship with NMS_PAYLOAD_FILTER_EXPR table. This column, PAYLOAD_FILTER is populated based on index col value of NMS_PAYLOAD_FILTER_EXPR The unique key needs to be relaxed in order to proceed with the inserts else we hit the following issue: "2023-04-10 01:35:02.749 ERROR [org.hibernate.engine.jdbc.batch.internal.BatchingBatch] HHH000315: Exception executing batch [java.sql.BatchUpdateException: The statement was aborted because it would have caused a duplicate key value in a unique or primary key constraint or unique index identified by 'UK_HJWHE1QKYLIS421SH7BTMYPH1' defined on 'NMS_DAMPEN_CONFIG'.], SQL: insert into NMS_DAMPEN_CONFIG (UUID, VERSION, ENABLE, HR_INTERVAL, MIN_INTERVAL, PAYLOAD_FILTER, SEC_INTERVAL, ID) values (?, ?, ?, ?, ?, ?, ?, ?){noformat} ( https://hibernate.atlassian.net/browse/HHH-16502#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16502#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#100223- sha1:77dfe11 )