Monday, September 3, 2007

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

Unidirectonal one-to-one (join table) association

Hibernate Doc (Chap 8.3.3)

::Relationship::
person(one) -> address(one)

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

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

::Annotation::

@Entity
@Table(name = "PERSON")
@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;  
}



::Generated SQL::
- person.getAddress();

select person0_.personId as personId2_1_, person0_1_.addressId as addressId3_1_, address1_.addressId as addressId4_0_ 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 where person0_.personId=?

[Association Mapping List]

6 comments:

Prats said...

thanks for the psot

luke said...

simple but very handy reference. arigato gozaimasu

Anonymous said...

this one-to-one via join table does not work for me with toplink. Is there any difference using hiberate or toplink for jpa? thx

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Asad said...

That is good post..well i am having a problem and it is driving me nuts.
i have a scenario in which each product it link to some other product.
table = product
id (primary key),
link(pointing to id)
this link can and cannot be null.its kind of parent child realtion in one table..after searching and found nothing i thought may b my design is bad so i split the product table
table = product
id

table = pr_link
prod_id ()
link_id ()
both are foreign keys from product table. it is one to one relation and iam unable to fix it..please help thank you..

Anonymous said...

Thanks it works great.