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Re: [eclipselink-users] colon object and then insert
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Hello,
You have not mentioned how aId is mapped within B, but it is likely
mapped as an @Id. If so, you always have to set the aId field directly,
as the provider has no way of knowing it comes from the A object. If
you are using JPA 2.0, you can use M:1 and 1:1 mappings in the primary
key, so that the provider knows that the foreign key to A is to be used
as the primary key. Since EmbeddedIds still do not allow relationship
mappings, it will not change, but the M:1 mapping in B to A would need
to be annotated with a @MapsId("aId") where "aId" refers to the
attribute name within the embeddedId class. This will cause the aID
foreign key to be populated with the value from the reference A.
If you are not using JPA 2.0, you will need to set your ID mapping as
insertable/updateable=false, and then set the B->A relationship so that
it writes the foreign key. This will mean that a refresh will need to
be done on B after a flush inorder to get the embeddedId's aId value set
(or a postPersist used to set it)
Best Regards,
Chris
Weiquan Yuan wrote:
Hi,
I am having problems on colone object using eclipseLink
objectcopyingPolicy.
I have an entity A with children entity B, and B have multiple
children entity C , D. Here is the roughly for the structure.
A has oneToMany relationship to B, and A has pk aId annotated as
generatedValue AUTO. B is annotated as privateOwned,
@OneToMany(mappedBy="a", cascade = ALL, targetEntity=B.class)
B has oneToMany relationship to C, and B has @EmbeddedId pk class
which including aId (aId is FK and part of PK)and bId, and C has
@EmbeddedId pk class which include aId(aId is FK and part of PK),
bId(bId is FK and part of PK), cId
B has oneToMany relationship to D, D has @EmbeddedId pk class which
including aId and bId (aId and bId is FK and part of PK)and dId.
when using the snippet below to colon object and then persist it,
===================
private EntityManagerFactory emf =
Persistence.createEntityManagerFactory("brancoch");
private EntityManager em = emf.createEntityManager();
// first step, tried to retrieve one existing one from Db
A a = findAById(new String("10005699"));
String xml = getXml(a);
System.out.println(xml);
// next step, colon A and then insert colonedA
a = fromXml(xml);
A colonedA = clone(a, em);
em.getTransaction().begin();
em.persist(colonedA);
em.getTransaction().commit();
-------------------------------------
private A clone(A s, EntityManager em) {
EntityManagerImpl eme = (EntityManagerImpl)
em.getDelegate();
Session session = eme.getSession();
ObjectCopyingPolicy p = new ObjectCopyingPolicy();
p.cascadePrivateParts();
s = (A) session.copyObject(s, p);
return s;
}
========================================================
In the console, i can see that it clearly insert A with auto generated
aId, but when inserting B, it insert null for aId, I use prePersist
callback to set bId. for my case, how can I set aId when inserting
object B, I have to use postPersist callback in object A to set it up?
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