Hibernate: Annotation one-to-one (join table)

Bidirectonal one-to-one (join table) association (very unusual)

Hibernate Doc (Chap 8.5.2)


::Relationship::
person(one)(mapping owner) <-> address(one)

::DB Schema::
person(personId)
address(addressId)
personaddress(personId, addressId)

::Java Operation::
person.getAddress();
address.getPerson();

::Annotation::

@Entity
@Table(name = "PERSON")
public class Person {

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column(name = "personId")
  private int id;

  @OneToOne(optional=true)
  @JoinTable(name="PersonAddress",
    joinColumns = {
      @JoinColumn(name="personId", unique = true)           
    },
    inverseJoinColumns = {
      @JoinColumn(name="addressId")
    }     
  )
  private Address address;
}

@Entity
@Table(name = "ADDRESS")
public class Address {

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column(name = "addressId")
  private int id;

  @OneToOne(optional=true, mappedBy="address") // pointing to Person's address field
  private Person person;   
}

::Generated SQL::
- person.getAddress();
select person0_.personId as personId2_2_, person0_1_.addressId as addressId3_2_, address1_.addressId as addressId4_0_, address1_1_.personId as personId3_0_, person2_.personId as personId2_1_, person2_1_.addressId as addressId3_1_ from PERSON person0_ left outer join PersonAddress person0_1_ on person0_.personId=person0_1_.personId left outer join ADDRESS address1_ on person0_1_.addressId=address1_.addressId left outer join PersonAddress address1_1_ on address1_.addressId=address1_1_.addressId left outer join PERSON person2_ on address1_1_.personId=person2_.personId left outer join PersonAddress person2_1_ on person2_.personId=person2_1_.personId where person0_.personId=?

- address.getPerson();
select address0_.addressId as addressId4_2_, address0_1_.personId as personId3_2_, person1_.personId as personId2_0_, person1_1_.addressId as addressId3_0_, address2_.addressId as addressId4_1_, address2_1_.personId as personId3_1_ from ADDRESS address0_ left outer join PersonAddress address0_1_ on address0_.addressId=address0_1_.addressId inner join PERSON person1_ on address0_1_.personId=person1_.personId left outer join PersonAddress person1_1_ on person1_.personId=person1_1_.personId left outer join ADDRESS address2_ on person1_1_.addressId=address2_.addressId left outer join PersonAddress address2_1_ on address2_.addressId=address2_1_.addressId where address0_.addressId=?

[Association Mapping List]