JPA @OneToMany设置空ID

Question

我一直在尝试通过spring-data-jpa中的额外列实现@ManyToMany关系。

就像在这个繁琐的https://hellokoding.com/jpa-many-to-many-extra-columns-relationship-mapping-example-with-spring-boot-hsql/中一样 ，但是不幸的是，在我的情况下它不起作用。

这是我的课程：

@Entity
public class AccountEvent implements Serializable {

  @Id
  @ManyToOne(optional = false)
  @JoinColumn(name = "event_id")
  private Event event;

  @Id
  @ManyToOne(optional = false)
  @JoinColumn(name = "account_id")
  private Account account;

  @Column(name = "is_confirmed", nullable = false)
  private boolean isConfirmed;

  public AccountEvent() {
  }

  public AccountEvent(Event event, Account account) {
    this.event = event;
    this.account = account;
    this.isConfirmed = false;
  }

  public AccountEvent(Event event, Account account, boolean isConfirmed) {
    this.event = event;
    this.account = account;
    this.isConfirmed = isConfirmed;
  }

  public Event getEvent() {
    return event;
  }
  public void setEvent(Event event) {
    this.event = event;
  }

  public Account getAccount() {
    return account;
  }
  public void setAccount(Account account) {
    this.account = account;
  }

  public boolean isConfirmed() {
    return isConfirmed;
  }
  public void setConfirmed(boolean confirmed) {
    isConfirmed = confirmed;
  }
}

帐户实体

@Entity
public class Account {

  @Id
  @Column(name = "id", updatable = false, nullable = false)
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "user_id_seq")
  @SequenceGenerator(name = "user_id_seq", sequenceName = "user_id_seq", allocationSize = 1)
  private Long id;

[...]

  @OneToMany(mappedBy = "account")
  private Set<AccountEvent> accountEvents;

}

事件实体

@Entity
public class Event implements Serializable {

  @Id
  @NotNull
  @Column(name = "id", updatable = false)
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "event_id_seq")
  @SequenceGenerator(name = "event_id_seq", sequenceName = "event_id_seq", allocationSize = 1)
  private Long id;

[...]

  @OneToMany(mappedBy = "event", fetch = FetchType.EAGER, cascade = CascadeType.ALL)
  private Set<AccountEvent> accountEvents;
}

以及我尝试保留此数据的方法。

  @Override
  @Transactional(propagation = Propagation.REQUIRES_NEW)
  public void signUpForAnEvent(String login, Event event) throws AppException {
    Account account = accountRepository.findByLogin(login);

    AccountEvent accountEvent = new AccountEvent(event, account);
    event.getAccountEvents().add(accountEvent);

    logger.info("Signing up user: " + account.toString() + " , for event: " + event.toString());
    eventRepository.save(event);
  }

每当我尝试保存（保存方法）数据时，我都会收到此类异常

org.postgresql.util.PSQLException: ERROR: null value in column "event_id" violates not-null constraint
Szczegóły: Failing row contains (f, null, null).

我究竟做错了什么？