[jboss-user] [Persistence, JBoss/CMP, Hibernate, Database] - How to map @OneToOne with Primary key association

[jfrankman]

I have two classes Client and Drivingdistance with a one to one association. The id of the Client is the PK and FK in DrivingDistance. My mapping annotations are as follows:

Client class:
@Table(name="FBCLIENT")
  | @Name("client")
  | @Scope(ScopeType.SESSION)
  | public class ClientVO implements Serializable
  | {
  | 	@Id @NotNull @Column(name="CLIENTID")
  | 	public Long getId() {
  | 		return id;
  | 	}
  |     @OneToOne(cascade = CascadeType.ALL)
  |     @PrimaryKeyJoinColumn()
  |     public DrivingDistanceVO getDrivingDistance()
  | 	{
  | 		return drivingDistance;
  | 	}
  | ...}


Driving Distance
@Entity
  | @Table(name="FBDRVDSTNC")
  | @Name("drivingDistance")
  | public class DrivingDistanceVO implements Serializable
  | {
  | 	@Id @Column(name="CLIENTID")
  |                @GeneratedValue(generator="foreign")
  |               @GenericGenerator(name="foreign", strategy = "foreign", parameters={ @Parameter(name="property", value="client") })
  | 	public Long getId() {
  | 		return id;
  | 	}
  | 	@OneToOne(mappedBy="drivingDistance")
  | 	public ClientVO getClient()
  | 	{
  | 		return client;
  | 	}
  | }

If I try to assign a driving distance to the client and save it:

        ClientVO client=(ClientVO)q.getSingleResult();
  |         
  |         
  |         DrivingDistanceVO vo2=new DrivingDistanceVO();
  |         //vo2.setId(new Long(225415));
  |         vo2.setLocation1(new Long(48254));
  |         vo2.setLocation2(new Long(171767));
  |         vo2.setUriString("http://www.google.com/intl/en_ALL/images/logo.gif");
  |         if (client.getDrivingDistance()==null)
  |         {
  |         client.setDrivingDistance(vo2);
  |         em.merge(client);
  |         }

I get the following error:

javax.persistence.PersistenceException: org.hibernate.id.IdentifierGenerationException: attempted to assign id from null one-to-one property: client
  | 	at org.hibernate.ejb.AbstractEntityManagerImpl.throwPersistenceException(AbstractEntityManagerImpl.java:567)
  | 	at org.hibernate.ejb.AbstractEntityManagerImpl.merge(AbstractEntityManagerImpl.java:210)
  | 	at com.idfbins.nexus.business.test.ClientDrivingDistanceTest.testClientDriveDistancePersist(ClientDrivingDistanceTest.java:63)
  | Caused by: org.hibernate.id.IdentifierGenerationException: attempted to assign id from null one-to-one property: client
  | 	at org.hibernate.id.ForeignGenerator.generate(ForeignGenerator.java:44)
  | 	at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:98)
  | 	at org.hibernate.event.def.DefaultMergeEventListener.entityIsTransient(DefaultMergeEventListener.java:165)
  | 	at org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:102)
  | 	at org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:51)
  | 	at org.hibernate.impl.SessionImpl.fireMerge(SessionImpl.java:679)
  | 	at org.hibernate.impl.SessionImpl.merge(SessionImpl.java:663)
  | 	at org.hibernate.impl.SessionImpl.merge(SessionImpl.java:667)
  | 	at org.hibernate.ejb.AbstractEntityManagerImpl.merge(AbstractEntityManagerImpl.java:201)
  | 	... 22 more
  | ... Removed 21 stack frames

I have poured over the documentation and forums but can't understand why this is failing. I have seen others ask similar questions, but have not found any answers. I have noticed that if I call em.persist instead of em.merge I do not get this error. However, I thought that since the client already exists in the database that merge would be the appropriate method to call.

So, can anyone explain why I am getting the message "org.hibernate.id.IdentifierGenerationException: attempted to assign id from null one-to-one property: client
" even after I have assigned the driving distance to the client ( client.setDrivingDistance(vo2);
)

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