Abid Hussain wrote:
Hi Armin,
thanks for help.
Just to be sure that I got the point: When there is a 'proxy="dynamic"'
in the class-descriptor, proxies are always used when more than one
object is queried?
The returned persistence capable object is always a proxy object, even
if the query result returns a single object.
In my opinion using a proxy on class-descriptor level (persistence
capable object proxy) doesn't give much advantage, because OJB always
perform the full query and only materialize the object identity from the
result set.
I thought that proxies are only used when retrieving a collection
through a relation (1:n or m:n, e.g. ShoppingCart.getArticles() - see
below)...
If you declare proxy="true" on collection-/reference-descriptor level
(1:1, 1:n or m:n relation) then yes you are right.
regards,
Armin
Regards,
Abid
Armin Waibel schrieb:
Hi Abid,
Abid Hussain wrote:
Hi again,
I think this issue has to something with the materialization of
objects (when using proxies). But I thought that proxies are only
used, when retrieving a corresponding collection of an object (in 1:n
and m:n relations, e.g. ShoppingCart.getArticles()...).
What I'm doing when using findAll() (see below) is something like
SELECT * FROM <tablename>. I thought, in this case no proxies are
used???
You are using dynamic proxies for all Account_2 objects:
<class-descriptor class="modulverwaltung.beans.Account_2"
table="ACCOUNT_2" proxy="dynamic">
The query result collection isn't a proxy object. Instead each result
object is a proxy object of persistence capable object (Account_2
object). In most cases this doesn't have an performance advantage.
If you now store each of these objects without materialization (e.g.
your log.debug() force the materialization of the object) OJB thinks
that the object didn't change and skip the update.
regards,
Armin
Regards,
Abid
Abid Hussain schrieb:
Hi everybody,
I have written a storeAll()-method in a dao to store all given
objects in one transaction (you find the code at the end of this mail).
Now please have a look at the following lines of code:
Account_2DAO dao1 = new Account_2DAO("DB1");
Collection<Account_2> accounts = dao1.findAll(Account_2.class);
logger.debug(accounts);
Account_2DAO dao2 = new Account_2DAO("DB2");
dao2.storeAll(accounts);
As you see, that there are two daos initialized. The first (dao1)
retrieves all objects (using findAll()) from a database (DB1). The
second (dao2) stores all retrieved objects into another database (DB2).
The findAll()-method works fine.
But the storeAll()-method only works when the line of code
logger.debug(accounts);
is called. If not, no data is inserted.
Any ideas what's going wrong (you find the class-descriptor file
below)?
Regards,
Abid
Code of storeAll():
public void storeAll(Collection<T> valueObjects)
throws PersistentStoringException {
if (valueObjects != null) {
try {
broker.beginTransaction();
for (T valueObject : valueObjects) {
broker.store(valueObject, ObjectModification.INSERT);
}
broker.commitTransaction();
} catch (Exception e) {
broker.abortTransaction();
throw new PersistentStoringException(
"Error while storing objects.\n" + e);
} finally {
if (broker != null && !broker.isClosed())
broker.close();
}
}
}
Class-descriptor of Account_2:
<class-descriptor class="modulverwaltung.beans.Account_2"
table="ACCOUNT_2" proxy="dynamic">
<field-descriptor name="id" column="ID" primarykey="true"
autoincrement="true" sequence-name="Account_Id_Seq" />
<field-descriptor name="username" column="Username"
jdbc-type="VARCHAR" />
<field-descriptor name="role" column="Rolle" jdbc-type="VARCHAR" />
</class-descriptor>
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
