Hibernate - In a one-to-many relationship, a child loses references to the parent when updating

Question

As in the title, when performing the update operation, the previous child loses the reference to the parent.

Parent side

@OneToMany(cascade =CascadeType.ALL)
@JoinColumn(name = "individual_id")
private List<ContactMedium> contactMedium;

Children side

@Entity
@Table(name = "contactMedium")
@Data
@AllArgsConstructor
@NoArgsConstructor
public class ContactMedium 
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id ;

    @ManyToOne
    private Individual individual;

Patch operation

 public Individual patch(Individual individual, Long id) {
        Individual objectToSave = individual;
        objectToSave.setId(id);
        return individualRepository.save(objectToSave);
    }

When updating, the previous property loses references to the child. How can I prevent this?

Why do you need to update the id when you are updating the parent? — Shiva kumar, Mar 29 '21 at 11:19
I dont want to update the id, I just need two references to my individual id — Grafik Krystian, Mar 29 '21 at 11:29
What do you mean by 'the previous child'? Is the 'previous child' missing from the list when you're making the update? — crizzis, Mar 29 '21 at 14:48

score 0 · Answer 1 · answered Mar 29 '21 at 11:11

0

Often one use mappedBy as parameter to @OneToMany instead of @JoinColumn to make the relationship two-ways.

Can you please try to change

@OneToMany(cascade =CascadeType.ALL)
@JoinColumn(name = "individual_id")
private List<ContactMedium> contactMedium;

to

@OneToMany(mappedBy = "individual", cascade =CascadeType.ALL)
private List<ContactMedium> contactMedium;

and see if that worked better?

answered Mar 29 '21 at 11:11

Kaj Hejer

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4
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Unfortunately, it is unchanged – Grafik Krystian Mar 29 '21 at 11:15
OK... You might want to turn on logging of the generated sql and see when is different from the expected sql. – Kaj Hejer Mar 29 '21 at 11:18

Jignesh M. Khatri · Accepted Answer · 2021-03-29T11:26:56.367

0

Your mappings seems wrong. Ideally they should be as below:

@Entity
@Table(name = "contactMedium")
@Data
@AllArgsConstructor
@NoArgsConstructor
public class ContactMedium 
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id ;

    @ManyToOne 
    @JoinColumn
    private Individual individual;

and

@OneToMany(mappedBy = "individual", cascade = CascadeType.ALL)
private List<ContactMedium> contactMedium;

You need to save the ContactMedium and Individual will automatically be saved. Here ContactMedium has the foreign key reference to Individual (and that is what is depicted in your database table screenshot).

edited Mar 29 '21 at 11:26

answered Mar 29 '21 at 11:18

Jignesh M. Khatri

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It didn't help, my writing is the opposite but it's not wrong – Grafik Krystian Mar 29 '21 at 11:27
You have `individual_id` in `contact_medium` table right? And `individual` table doesnot have `contact_medium_id`? – Jignesh M. Khatri Mar 29 '21 at 11:28

Med Elgarnaoui · Answer 3 · 2021-03-29T11:43:41.697

0

I think you must add the @OneToMany(mappedBy="individual" , cascade =CascadeType.PERSIST) and the @JoinColumn in the @ManyToOne as below:

@OneToMany(mappedBy = "individual", cascade =CascadeType.PERSIST)
private List<ContactMedium> contactMedium;

@ManyToOne
@JoinColumn(name = "individual_id")
private Individual individual;

edited Mar 29 '21 at 11:43

answered Mar 29 '21 at 11:21

Med Elgarnaoui

1,612
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It didn't help, my writing is the opposite but it's not wrong – Grafik Krystian Mar 29 '21 at 11:27
can you try before update getting the list getcontactMedium and re-assign it to objectTosave, like : 'objectToSave.setContactMedium(individual.getContactMedium());' – Med Elgarnaoui Mar 29 '21 at 11:35
ok I suggest to try with CascadeType.PERSIST instead or CascadeType.ALL – Med Elgarnaoui Mar 29 '21 at 11:39

score 0 · Answer 4 · answered Dec 10 '21 at 04:25

0

You should retrieve the entity from the database using the ID first and then update the specific fields and persist the updated entity back.

answered Dec 10 '21 at 04:25

Upesh M

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Hibernate - In a one-to-many relationship, a child loses references to the parent when updating

4 Answers4