Hello,

I've got the following table structure from an existing project which is running with EJB2.0 Entities. I'm migrating those entities to EJB3.0 JPA Objects. However, I'm faced to the following problem :

I've got a OneToOne bidirectionnal association between class A and class B. The fact is that the database table is made like

this :
table A(col_A_ID, col_A_1, col_A_2, col_B_ID)
table B(col_B_ID, col_B_1, col_B_2, col_A_ID)

We've got a primary key for table A (col_A_ID) and a primary key for table B (col_B_ID)
We've got a foreign key for table A (col_B_ID) and a foreign key for table B (col_A_ID)

I've sawn samples for Hibernate with only one side of the relation mapping the foreign key, but never both sides.

The following code emphasis the fact that Table A.col_B_ID is missing, there will be only Table B.col_A_ID :
---
public class A {
...
@OneToOne(mappedBy="a")
private B b;
...
}
---
public class B {
...
@OneToOne
@JoinColumn(name="col_A_ID")
private A a;
...
}
---

Is it possible to manage to do OneToOne bidir with 2 foreign keys (one for each side) with JPA & Hibernate ? Why is it not

done by default as with EJB2.0 ? If it is possible to still do such a thing, is it much more costly concerning the

performances of the application ?

Regards,
Blured.

I've managed to do it using the following code :
---
public class A {
...
@OneToOne
@JoinColumn(name="col_B_ID")
private B b;
...
}
---
public class B {
...
@OneToOne
@JoinColumn(name="col_A_ID")
private A a;
...
}
---

However, as you can see, there is no mappedBy attribute. What does it implies ?

Regards,
Blured.