@OneToOne With @JoinColumn that holds only the UUID instead of the whole object

Question

I'm using Java + Spring + Hibernate

When testing the following code, I'm getting an error:

javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: could not get a field value by reflection getter of com.XXX.XXX.entity.Policy.id

@Entity
@Table(name = "assignment")
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class Assignment extends BaseEntity {

    @Id
    @Column(name = "id")
    @Type(type = "pg-uuid")
    @NotTracked
    private UUID id;

    @OneToOne(targetEntity = Policy.class)
    @JoinColumn(name = "policy_id", nullable = false, referencedColumnName = "policy_id")
    @OnDelete(action = OnDeleteAction.CASCADE)
    @TrackedEntity(isIdentityField = true)
    private UUID policyID;
}

@Entity
@Table(name = "policy")
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE, region = "policy")
@Inheritance(strategy = InheritanceType.JOINED)
public class Policy extends BaseEntity {

    @Id
    @Column(name = "policy_id")
    @Type(type = "pg-uuid")
    @NotTracked
    private UUID id;

    ...
    ...
    ..

}

When changing the private UUID policyID; from UUID to Policy, its working just fine, is there a way to set somehow a reference to specific object inside Policy as ID instead of holding the whole object of policy inside the Assignment object?

Answer 1

It is possible to include just the UUID, but it will not be a hibernate managed FK any longer. I don't advise this as you want Hibernate to manage your FK.. You would simply change Assignment to:

@Entity
@Table(name = "assignment")
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class Assignment extends BaseEntity {

    @Id
    @Column(name = "id")
    @Type(type = "pg-uuid")
    @NotTracked
    private UUID id;

    @Column(name="policy_id")
    private UUID policyID;
}

With that being said, you will lose all Cascade options and FK check constraints against this field unless you add them to your database manually.