one-to-one with just unique keys

jaynes · **Posted:** Wed Jan 21, 2004 9:38 am

I have a one-to-one relationship, but the relation is defined by unique keys rather than primary keys. The DB tables are:

Code:

create table CG_USER
(
  USER_ID   NUMBER not null, (primary key, Hibernate generated)
  ORACLE_ID VARCHAR2(30) not null (unique)
)
create table EMPLOYEE (read only, not under my control)
(
  EMPLID    VARCHAR2(30) not null, (primary key)
  UNIQUE_ID VARCHAR2(30) not null  (unique)
)

The classes are:
CgUser - id, oracleId, employee
Employee - emplid, uniqueId

The one-to-one relation is defined by ORACLE_ID and UNIQUE_ID. The Employee property of CgUser may be null.

Can this relation be mapped by Hibernate? If not, any suggestions as to how best to handle it? Thanks.

emmanuel · **Posted:** Wed Jan 21, 2004 10:03 am

Have a look at the property-ref attribute

jaynes · **Posted:** Wed Jan 21, 2004 12:30 pm

property-ref: The name of a property of the associated class that is joined to the primary key of this class.

I'm not sure how that helps, since it still involves a primary key.

I can see how to do this if I get rid of the synthetic key, USER_ID, and simply use the ORACLE_ID field as the PK. But then I'm using something that has a domain meaning as a key. I prefer not to do that in tables that I control.

emmanuel · **Posted:** Wed Jan 21, 2004 12:42 pm

I read too fast.
I don't think you can. Do a plain HQL query for that.