From: <gdurand_at_hmdc.harvard.edu>
Date: Wed, 27 Sep 2006 17:57:20 -0400

Hi,

I'm am trying a very simple example and am getting a problem
(I am using glassfish v2 milestone 1):

Our DB has a Study entity which has a one to many relationship
with a FileCategory entity.

When I try to add a FileCategory to an existing study:

         Collection categories = study.getFileCategories();

         FileCategory c = new FileCategory();
         c.setName( "test" );


         c.setStudy(study);
         categories.add(c);

         em.merge(study);

I am getting:

Exception Details:
oracle.toplink.essentials.exceptions.OptimisticLockException
    Exception Description: The object
[edu.harvard.hmdc.vdcnet.study.FileCategory_at_1f1c748] cannot be merged
because it has changed or been deleted since it was last read.
{3}Class> edu.harvard.hmdc.vdcnet.study.FileCategory



Any ideas why this is happening, since the FileCategory doesn't exist
in the first place? (I have seen an example in the O'Reilly book that
pretty much does just this)?

Thanks,
Gustavo