JPA not saving foreign key to @OneToMany relation

Question

I'm using Spring with Hibernate as a JPA provider and are trying to get a @OneToMany (a contact having many phonenumbers) to save the foreign key in the phone numbers table. From my form i get a Contact object that have a list of Phone(numbers) in it. The Contact get persisted properly (Hibernate fetches an PK from the specified sequence). The list of Phone(numbers) also gets persisted with a correct PK, but there's no FK to the Contacts table.

public class Contact implements Serializable {

    @OneToMany(mappedBy = "contactId", cascade = CascadeType.ALL, fetch=FetchType.EAGER)
    private List<Phone> phoneList;

}

public class Phone implements Serializable {

    @JoinColumn(name = "contact_id", referencedColumnName = "contact_id")
    @ManyToOne
    private Contact contactId;

}

@Repository("contactDao")
@Transactional(readOnly = true)
public class ContactDaoImpl implements ContactDao {

    @Transactional(readOnly = false, propagation = Propagation.REQUIRES_NEW)
    public void save(Contact c) {
        em.persist(c);
        em.flush();
    }
}


@Controller
public class ContactController {
    @RequestMapping(value = "/contact/new", method = RequestMethod.POST)
    public ModelAndView newContact(Contact c) {
        ModelAndView mv = new ModelAndView("contactForm");
        contactDao.save(c);
        mv.addObject("contact", c);
        return mv;
    }
}

Hopefully I got all of the relevant bits above, otherwise please let me know.

score 29 · Accepted Answer · edited Apr 19 '19 at 18:32

29

You have to manage the Java relationships yourself. For this kind of thing you need something like:

@Entity
public class Contact {
  @Id
  private Long id;

  @OneToMany(cascade = CascadeType.PERSIST, mappedBy = "contact")
  private List<Phone> phoneNumbers;

  public void addPhone(PhoneNumber phone) {
     if (phone != null) {
        if (phoneNumbers == null) {
            phoneNumbers = new ArrayList<Phone>();          
        }
        phoneNumbers.add(phone);
        phone.setContact(this);
     }
  }

  ...
}

@Entity
public class Phone {
  @Id
  private Long id;

  @ManyToOne
  private Contact contact;

  ...
}

edited Apr 19 '19 at 18:32

archit kumar

21
9

answered May 02 '09 at 09:20

cletus

616,129
168
910
942

5

Is the `addPhone` method correct? It looks to me like the null check is in the wrong place. – Mark Byers Jan 11 '11 at 13:03
phone.setContact(this) - it colud be a memory leak? or not? – Feb 05 '14 at 11:56
6

Why do I have to manage the java relationship myself? What if I have a unidirectional relationship? – Fagner Brack Oct 10 '14 at 21:51
@FagnerBrack If you do not have `@ManyToOne` on the Phone class, hibernate will create a table to manage the relationship which will gamed like `CONTACT_PHONE` and hibernate will insert the required records to that table. – Pavan Kumar Jun 17 '21 at 12:57

score 6 · Answer 2 · edited Jan 11 '11 at 13:46

In reply to Cletus' answer. I would say that it's important to have the @column annotation on the id fields, as well as all the sequence stuff. An alternative to using the mappedBy parameter of the @OneToMany annotation is to use the @JoinColumn annotation.

As a kinda aside your implementation of addPhone needs looking at. It should probably be something like.

public void addPhone(PhoneNumber phone) {
    if (phone == null) {
        return;
    } else {
        if (phoneNumbers == null) {
            phoneNumbers = new ArrayList<Phone>();
        }
        phoneNumbers.add(phone);
        phone.setContact(this);
    }
}

score 5 · Answer 3 · answered Dec 01 '17 at 07:06

If the Contact-Phone relationship is unidirectional, you can also replace mappedBy in @OneToMany annotation with @JoinColumn(name = "contact_id").

@Entity
public class Contact {
  @Id
  private Long id;

  @OneToMany(cascade = CascadeType.PERSIST)
  @JoinColumn(name = "contact_id")
  private List<Phone> phoneNumbers;

  // normal getter/setter
  ...
}

@Entity
public class PhoneNumber {
  @Id
  private Long id;

  ...
}

Similar in JPA @OneToMany -> Parent - Child Reference (Foreign Key)

score 2 · Answer 4 · edited Apr 19 '18 at 19:44

2

I don't think the addPhone method is necessary, you only have to set the contact in the phone object:

phone.setContact(contact);

edited Apr 19 '18 at 19:44

SkyWalker

28,384
14
74
132

answered Sep 10 '15 at 06:34

Camel

21
1

score 1 · Answer 5 · answered Feb 20 '20 at 16:34

1

If you want your relationship unidirectional i.e. can navigate from Contact to Phone's only, you need to add

@JoinColumn(name = "contact_id", nullable = false)

Under your @OneToMany on your parent entity.

nullable = false IS VITAL if you want hibernate to populate the fk on the child table

answered Feb 20 '20 at 16:34

Tom Chamberlain

2,955
20
24

This one really helped me. Nullable automatically made sure to insert key in child table. Ur a savior!! – vkt Oct 23 '20 at 19:16

score 0 · Answer 6 · answered Apr 06 '20 at 19:59

Try this sample:

@Entity
public class Contact {
    @Id
    private Long id;

    @JoinColumn(name = "contactId")
    @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
    private Set<Phone> phones;
}

@Entity
public class Phone {
    @Id
    private Long id;
    private Long contactId;
}

Saibanna Biradar · Answer 7 · 2023-01-22T06:28:13.897

0

In JPA this helped me

contact.getPhoneList().forEach(pl -> pl.setContact(contact));
contactRepository.save(contact);

edited Jan 22 '23 at 06:28

answered Jan 22 '23 at 06:26

Saibanna Biradar

1
2

JPA not saving foreign key to @OneToMany relation

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