[hibernate] OneToOne add a new child :o(

[Alessandro Ilardo]

Hi there,
I'm new with persistence, and I'm having a problem updating an object which has a chlid object referenced by a OneToOne relation.
When I update the child properties a new row is added into the table, while I'd like just udpate the existing one.

The father

@Entity
@Inheritance(strategy =InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="type",discriminatorType=DiscriminatorType.STRING)
@DiscriminatorValue("simple")
@Table(name="USER")
public class User implements java.io.Serializable {
    private long id;
    private UsrRole userRole;
    ....
 
    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name="role_fk")
    @OnDelete(action=OnDeleteAction.CASCADE)
    public UsrRole getUserRole() {
        return userRole;
    }
    
    public void setUserRole(UsrRole userRole) {
        this.userRole = userRole;
    }
    ....

the child

@Entity
@Table(name="USER_ROLE")
public class UsrRole implements java.io.Serializable {
    private long id;
    ...
 
    @Id
    @GeneratedValue
    @Column()
    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }
    ...

On my session bean I call the merge method on the user instance.
Any suggestions?

Thanks in advance