creating bidirectional @OneToOne mapping with derived id

kristian · **Posted:** Mon Nov 23, 2009 5:14 am

i'm using the latest hibernate release (3.5.beta.2) to test the latest JPA 2.0 features but i fail to create a bidirectional @OneToOne mapping with a derived id. whenever i try to do so hibernate will generate a BLOB as the id of the dependent entity. can someone point me to the right solution or a working example.

thank you very much in advance.

Code:

@Entity
public class A
{
    @Id @GeneratedValue
    private Long id;

    @OneToOne(mappedBy="a")
    private B b;
}


@Entity
public class B
{
    @Id @OneToOne
    private A a;
}

mmerder · **Posted:** Mon Nov 23, 2009 5:23 am

Have you tried PrimaryKeyJoinColumn?

kristian · **Posted:** Mon Nov 23, 2009 5:29 am

Yes i did, but then i get the following exception on startup (ddl update)

Quote:

Referenced property not a (One|Many)ToOne: B.a in mappedBy of A.b

any ideas? thanks

mmerder · **Posted:** Mon Nov 23, 2009 5:31 am

As shown in the examples you don't need a mappedBy anymore (your id-column is also the foreign-key, so no need to tell hibernate a mappedBy).

kristian · **Posted:** Mon Nov 23, 2009 6:13 am

when i remove the mappedBy attribute the foreign-key is still created as BLOB (HsqlDB = VARBINARY) and i get an schema update error:

Quote:

[ERROR] SchemaUpdate Unsuccessful: alter table A add constraint FKC3B5EFE46F1961A6 foreign key (id) references B
[ERROR] SchemaUpdate Column types do not match in statement [alter table A add constraint FKC3B5EFE46F1961A6 foreign key (id) references B]

thanks for the help

mmerder · **Posted:** Mon Nov 23, 2009 6:52 am

Please drop your database tables before testing, as something seems to be wrong with letting hibernate update it.