mklinkj ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *created* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiNzEzOWU2YTk3... ) / Bug ( https://hibernate.atlassian.net/browse/HHH-16448?atlOrigin=eyJpIjoiNzEzOW... ) HHH-16448 ( https://hibernate.atlassian.net/browse/HHH-16448?atlOrigin=eyJpIjoiNzEzOW... ) After upgrading to Hibernate 6.2.0.Final, the unique attribute of `@JoinColumn` always behaves as true. ( https://hibernate.atlassian.net/browse/HHH-16448?atlOrigin=eyJpIjoiNzEzOW... ) Issue Type: Bug Affects Versions: 6.2.0 Assignee: Unassigned Attachments: HibernateUpgradeJoinColumnTest.zip Components: hibernate-core Created: 07/Apr/2023 15:35 PM Environment: * HSQLDB 2.7.1 * Hibernate 6.2.0.Final Priority: Major Reporter: mklinkj ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) Hello. There was no problem when using Hibernate 6.1.7.Final version, but after upgrading to Hibernate 6.2.0.Final, the unique property of @JoinColumn always operates as true. For example, two entities are: * MemberShipCard Entity @Entity public class MembershipCard {  @Id  @Column(name = "card_number" )  private String number; ​  @OneToOne  @JoinColumn(name = "user_email" )  private Student owner; ​  private LocalDateTime expiryDate; ​  private boolean enabled; } * Student Entity @Entity @EqualsAndHashCode(onlyExplicitlyIncluded = true ) public class Student {  (a)EqualsAndHashCode.Include @Id private String email;  private String name; ​  private LocalDateTime createDate; } Table creation SQL for MemberShipCard entity in Hibernate 6.1.7.Final ---------------------------------------------------------------------    create table membership_card (       card_number varchar (255) not null ,       enabled boolean not null ,       expiry_date timestamp (6),       user_email varchar (255),        primary key (card_number)    ) Table creation SQL for MemberShipCard entity in Hibernate 6.1.7.Final ---------------------------------------------------------------------    create table membership_card (       enabled boolean not null ,       expiry_date timestamp (6),       card_number varchar (255) not null ,       user_email varchar (255) unique ,  /* < -- Setting UNIUQE */        primary key (card_number)    ) Please inquire if there is any problem with the above operation. * Example Project * https://github.com/mklinkj/QnA/tree/master/JPA/HibernateUpgradeJoinColumn... * An example has been created in HSQLDB memory mode so you can check it right away ( https://hibernate.atlassian.net/browse/HHH-16448#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16448#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- sha1:916089c )