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[CDO/Hibernate] Examples: Why Query with CDOTransaction and not CDOView? [message #899553]

Wed, 01 August 2012 12:05

Christoph Keimel

Messages: 482
Registered: December 2010
Location: Germany

Senior Member

Hello

I have been studing the example projects org.eclipse.emf.cdo.examples.hibernate.*. I noticed that the queries in HibernateQueryTest are always created through a CDOTransaction.

public void testSimpleQueries() throws Exception
{
	CDOSession session = openSession();
	CDOTransaction transaction = session.openTransaction();
	{
	  CDOQuery cdoQuery = transaction.createQuery("hql", "from Product"); //$NON-NLS-1$  //$NON-NLS-2$
	  final List<Product> products = cdoQuery.getResult(Product.class);
	  assertEquals(NUM_OF_PRODUCTS, products.size());
	}
	...
	transaction.commit();
}

From the documentation I would have expected a CDOView to be used. Is there a special reason to use a CDOTransaction in this scenario? I.e. is it necessary to commit the selection because the objects are locked in some way or to free the query for garbage collection?

Greetings
Christoph

P.S. I needed to add org.eclipse.emf.ecore.change to the manifest of org.eclipse.emf.cdo.examples.hibernate.client for the tests to run.

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Re: [CDO/Hibernate] Examples: Why Query with CDOTransaction and not CDOView? [message #899575 is a reply to message #899553]

Wed, 01 August 2012 13:44

Martin Taal

Messages: 5468
Registered: July 2009

Senior Member

Hi Christoph,
No special reason, thanks for the note ecore.change, I hope to spend time on CDO Hibernate Store in august and solve
this and some other issues.

gr. Martin

On 08/01/2012 02:05 PM, Christoph Keimel wrote:
> Hello
>
> I have been studing the example projects org.eclipse.emf.cdo.examples.hibernate.*. I noticed that the queries in
> HibernateQueryTest are always created through a CDOTransaction.
> public void testSimpleQueries() throws Exception
> {
> CDOSession session = openSession();
> CDOTransaction transaction = session.openTransaction();
> {
> CDOQuery cdoQuery = transaction.createQuery("hql", "from Product"); //$NON-NLS-1$ //$NON-NLS-2$
> final List<Product> products = cdoQuery.getResult(Product.class);
> assertEquals(NUM_OF_PRODUCTS, products.size());
> }
> ...
> transaction.commit();
> }
> From the documentation I would have expected a CDOView to be used. Is there a special reason to use a CDOTransaction in
> this scenario? I.e. is it necessary to commit the selection because the objects are locked in some way or to free the
> query for garbage collection?
>
> Greetings
> Christoph
>
> P.S. I needed to add org.eclipse.emf.ecore.change to the manifest of org.eclipse.emf.cdo.examples.hibernate.client for
> the tests to run.

--

With Regards, Martin Taal

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