Hello!
I came accross the following situation: I am trying to create a
DbCustmer object (with a DbContact object as a member/field) from a
DbRawContact object, then mark the DbRawContact object so that it will
not be processed again next time.
try {
for (DbRawContact db : extent) {
if (db.getVersion().equals("0.0")) {
DbContact newContact = new DbContact(db);
DbCustomer customer = new DbCustomer();
customer.setProfile(newContact);
Transaction tx = pm.currentTransaction();
try {
tx.begin();
pm.makePersistent(customer);
db.setVersion("0.1");
tx.commit();
} finally {
if (tx.isActive()) {
tx.rollback();
}
}
}
}
} catch (Exception e) {
extent.closeAll();
}
extent.closeAll();
I am aware that I can only do transactions "in an entity group".
DbCustomer and DbContact will be in the same entity group, but i am
aware that DbRawContact is in a different entity group.
My question is: why didn't this transaction failed, if cross entity
group transactions are not supported? Instead the operation worked and
somehow I now have duplicate DbCustomer and DbContact objects in the
database. (note: DbRawContact objects contain no duplicates)
Below is a snippet of my DbCustomer and DbContact classes and the
setProfile() function.
@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class DbContact extends DbEntity {
....
@Persistent
private DbCustomer customer;
@Persistent
private boolean isCustomerProfile;
....
@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class DbCustomer extends DbEntity {
...
@Persistent(mappedBy = "customer")
@Order(extensions = @Extension(vendorName="datanucleus", key="list-
ordering", value="isCustomerProfile desc"))
private List<DbContact> contacts;
....
(i also ran across the problem that i can't have both owed "1-to-many"
and "1-to-1" relationships between the same two object types in JDO,
so i used a list (1-to-many) relationship like this:
- the first element is the "profile" (a "pseudo" 1-to-1
relationship);
- the other list elements model the 1-to-many relationship)
public void setProfile(Contact contact) {
if (contacts == null) {
contacts = new ArrayList<DbContact>();
}
if (contacts.size() == 0) {
DbContact dbContact = new DbContact(contact);
contacts.add(dbContact);
}
else {
DbContact dbContact = contacts.get(0);
dbContact.setCustomerProfile(true);
dbContact.copyEntityInfo(contact);
}
}
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