Bidirectional one-to-one relation fails on saving if @NotNull used

Question

I've the following one-to-one relation between User and UserSetup entities:

@Entity
class User {

   @OneToOne(mappedBy = "user", optional = false, cascade = ALL)
   private UserSetup setup;

   public User() {
      this.setup = new UserSetup(this);
   }
}

and

@Entity
public class UserSetup {

    @OneToOne(cascade = ALL)
    @JoinColumn(name = "USER_ID", nullable = false, unique = true)
    private User user;

    public UserSetup(User user) {
        this.user = user;
    }
}

It all works well, however if I add @NotNull to setup field in User class and call save on User repository it fails with:

Caused by: javax.persistence.RollbackException: Error while committing the transaction at org.hibernate.internal.ExceptionConverterImpl.convertCommitException(ExceptionConverterImpl.java:77) at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:71) at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:517) ... 64 more Caused by: javax.validation.ConstraintViolationException: Validation failed for classes [User] during update time for groups [javax.validation.groups.Default, ] List of constraint violations:[ ConstraintViolationImpl{interpolatedMessage='may not be null', propertyPath=setup, rootBeanClass=class User, messageTemplate='{javax.validation.constraints.NotNull.message}'} ]

What's going on? In debugger I see that setup field is set. Or maybe @NotNull should not be used with @OneToOne but optional should be used instead?

@XtremeBaumer, they are taken from sequence and `@Id` along with `@GeneratedValue(strategy = IDENTITY)` are used. — Opal, Mar 29 '18 at 08:26
You use `GenerationType.IDENTITY` when it is actually `GenerationType.SEQUENCE`? — XtremeBaumer, Mar 29 '18 at 08:28
@XtremeBaumer I may change it - does it affect the problem with `@NotNull` in you opinion? — Opal, Mar 29 '18 at 08:31
Well, I doubt that hibernate can create an ID if the generation type is wrong. This would mean, that it can't create a new `UserSetup` which is connected to the `User` — XtremeBaumer, Mar 29 '18 at 08:39
I'll try `SEQUENCE` however I doubt if it matters. Will let you know @XtremeBaumer. — Opal, Mar 29 '18 at 09:10
@XtremeBaumer it doesn't work with `SEQUENCE` at all. It fails at start of the context. — Opal, Mar 29 '18 at 09:17
I've almost no configuration files, everything is annotation-based. — Opal, Mar 29 '18 at 10:05
Well, you still have to create the `PersitenceContext` with some data — XtremeBaumer, Mar 29 '18 at 10:10

score 1 · Answer 1 · answered Mar 29 '18 at 08:36

1

From my understanding of how works Hibernate, that might not be possible, as Hibernate has to save one of the objects first, and when saving the first object the second one cannot be referenced in the database.

What you can do is put the @NotNull annotation to the setup field in the User class, as I understand you may not want to create a User without any setup, and the cascading would take care of removing the linked UserSetup object in case you remove the User.

answered Mar 29 '18 at 08:36

Vincz777

521
5
12

I don't get it. I already put `@NotNull` and it does not work as I stated in the question. – Opal Mar 29 '18 at 09:11
Sorry I mean put `@NotNull` in `User` class but remove it in `UserSetup` class. – Vincz777 Mar 29 '18 at 09:31
I've never had setup like this. – Opal Mar 29 '18 at 09:49
Remove `nullable = false` from UserSetup – Vincz777 Mar 29 '18 at 09:50

gargkshitiz · Answer 2 · 2018-03-29T09:46:02.790

1

In my opinion, @Notnull can not be used in User for UserSetup. That is because, User needs to be created first, and then the same user's ID would be used to save UserSetup as there is a foreign key constraint on it. Even though code wise, it is looking okay, involvement of DB to create the ID is one important factor here.

edited Mar 29 '18 at 09:46

answered Mar 29 '18 at 09:25

gargkshitiz

2,130
17
19

Thanks for the answer but is that what you think or you know for sure? – Opal Mar 29 '18 at 09:49
It is what I think. Having nullable = false in `@JoinColumn(name = "USER_ID", nullable = false, unique = true)` in UserSetup class makes sense, but having @NotNull for UserSetup in User class seems to create a catch-22 situation. – gargkshitiz Mar 29 '18 at 09:52
So you suggest that having either `@NotNull` or `nullable = false` on one side, makes sense? – Opal Mar 29 '18 at 10:06
Not exactly, there is a slight difference between these two ways. See https://stackoverflow.com/a/2726224/945214 and https://stackoverflow.com/a/7439544/945214 – gargkshitiz Mar 29 '18 at 10:28

Bidirectional one-to-one relation fails on saving if @NotNull used

2 Answers2