带有反向主外键级联的零到一单向休眠

Question

I'm facing a problem with Hibernate in Spring Boot.

We have 2 tables, users and user_info , with a Zero To One (so a nullable One To One) relation. The user_info has a primary foreign key that points to users.user_id :

CREATE TABLE `users` (
  `user_id` bigint(20) NOT NULL AUTO_INCREMENT,
  `username` varchar(45) NOT NULL,
  ...
  PRIMARY KEY (`user_id`)
) 

CREATE TABLE `users_info` (
  `user_id` bigint(20) NOT NULL,
  `name` varchar(45) NOT NULL,
  `surname` varchar(45) NOT NULL,
  `mail` varchar(45) DEFAULT NULL,
  ...
  PRIMARY KEY (`user_id`),
  KEY `fk_user_id_idx` (`user_id`),
  CONSTRAINT `fk_user_id` FOREIGN KEY (`user_id`) 
    REFERENCES `users` (`user_id`) 
    ON DELETE NO ACTION ON UPDATE NO ACTION
)

And these are the models:

@Entity
@Table(name = "users")
public class User implements UserDetails, Buildable<User.Builder> {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "user_id")
    private Long id;

    private String username;

    @Nullable
    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name="user_id")
    @JsonUnwrapped
    private UserInfo userInfo;


    ...
}


@Entity
@Table(name = "users_info")
public class UserInfo {
    @Id
    @Column(name = "user_id")
    private Long id;

    @Nullable
    private String name;

    @Nullable
    private String surname;

    ...
}

When I run the Spring application with this configuration, it throws an error saying:

org.hibernate.id.IdentifierGenerationException ids for this class must be manually assigned before calling save()

How can we cascade-persist the UserInfo instance if not null from the User entity?

Thanks for the answer(s)!

Answer 1

Your mapping is backwards. UserInfo should reference the user it's attached to, and be the owner of the association. And you should also say that its ID is also a foreign key to the user.

@Entity
@Table(name = "users")
public class User implements UserDetails, Buildable<User.Builder> {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "user_id")
    private Long id;

    private String username;

    @Nullable
    @OneToOne(mappedBy="user", cascade = CascadeType.ALL)
    @JsonUnwrapped
    private UserInfo userInfo;


    ...
}


@Entity
@Table(name = "users_info")
public class UserInfo {
    @Id
    @Column(name = "user_id")
    private Long id;

    @Nullable
    private String name;

    @Nullable
    private String surname;

    @OneToOne
    @MapsId
    private User user;
    ...