NHibernate + Jet Replica Database - Exception thrown when committing transaction ("a different object with the same identifier value was already associated with the session).

I have an application where we're using NHibernate and the NHibernate Jet Driver to open existing .MDB files (Access 2003 / Jet 4.0 databases), read some information and add some new records.

Unfortunately we have no control over the database format - so we're stuck having to support Jet.

The problem I'm facing is that when performing an insert it all works fine for a normal database, but if the database has been configured as either a design master or replica, then we get the following exception:

"a different object with the same identifier value was already associated with the session: 109, of entity: Data.Models.Tag"

   at NHibernate.Engine.StatefulPersistenceContext.CheckUniqueness(EntityKey key, Object obj)
   at NHibernate.Event.Default.AbstractSaveEventListener.PerformSaveOrReplicate(Object entity, EntityKey key, IEntityPersister persister, Boolean useIdentityColumn, Object anything, IEventSource source, Boolean requiresImmediateIdAccess)
   at NHibernate.Event.Default.AbstractSaveEventListener.PerformSave(Object entity, Object id, IEntityPersister persister, Boolean useIdentityColumn, Object anything, IEventSource source, Boolean requiresImmediateIdAccess)
   at NHibernate.Event.Default.AbstractSaveEventListener.SaveWithGeneratedId(Object entity, String entityName, Object anything, IEventSource source, Boolean requiresImmediateIdAccess)
   at NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.SaveWithGeneratedOrRequestedId(SaveOrUpdateEvent event)
   at NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.EntityIsTransient(SaveOrUpdateEvent event)
   at NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.PerformSaveOrUpdate(SaveOrUpdateEvent event)
   at NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.OnSaveOrUpdate(SaveOrUpdateEvent event)
   at NHibernate.Impl.SessionImpl.FireSaveOrUpdate(SaveOrUpdateEvent event)
   at NHibernate.Impl.SessionImpl.SaveOrUpdate(String entityName, Object obj)
   at NHibernate.Engine.CascadingAction.SaveUpdateCascadingAction.Cascade(IEventSource session, Object child, String entityName, Object anything, Boolean isCascadeDeleteEnabled)
   at NHibernate.Engine.Cascade.CascadeToOne(Object child, IType type, CascadeStyle style, Object anything, Boolean isCascadeDeleteEnabled)
   at NHibernate.Engine.Cascade.CascadeAssociation(Object child, IType type, CascadeStyle style, Object anything, Boolean isCascadeDeleteEnabled)
   at NHibernate.Engine.Cascade.CascadeProperty(Object child, IType type, CascadeStyle style, Object anything, Boolean isCascadeDeleteEnabled)
   at NHibernate.Engine.Cascade.CascadeCollectionElements(Object child, CollectionType collectionType, CascadeStyle style, IType elemType, Object anything, Boolean isCascadeDeleteEnabled)
   at NHibernate.Engine.Cascade.CascadeCollection(Object child, CascadeStyle style, Object anything, CollectionType type)
   at NHibernate.Engine.Cascade.CascadeAssociation(Object child, IType type, CascadeStyle style, Object anything, Boolean isCascadeDeleteEnabled)
   at NHibernate.Engine.Cascade.CascadeProperty(Object child, IType type, CascadeStyle style, Object anything, Boolean isCascadeDeleteEnabled)
   at NHibernate.Engine.Cascade.CascadeOn(IEntityPersister persister, Object parent, Object anything)
   at NHibernate.Event.Default.AbstractFlushingEventListener.CascadeOnFlush(IEventSource session, IEntityPersister persister, Object key, Object anything)
   at NHibernate.Event.Default.AbstractFlushingEventListener.PrepareEntityFlushes(IEventSource session)
   at NHibernate.Event.Default.AbstractFlushingEventListener.FlushEverythingToExecutions(FlushEvent event)
   at NHibernate.Event.Default.DefaultFlushEventListener.OnFlush(FlushEvent event)
   at NHibernate.Impl.SessionImpl.Flush()
   at NHibernate.Transaction.AdoTransaction.Commit()

I've read a little bit about the internals of replication, where some people suggest that replicated tables have extra columns or randomised identifiers, but I was under the impression most of the behaviour would be transparent to consuming applications?

Anybody have any suggestions on how to work around this / fix this problem?

ansaurus

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NHibernate + Jet Replica Database - Exception thrown when committing transaction ("a different object with the same identifier value was already associated with the session).

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