Oops... not sure if you are on the dev list. Copying this user as well...
From: Andrus Adamchik <andru..bjectstyle.org>
To: cayenne-deve..bjectstyle.org
Subject: Re: propogating (or posting events of) object changes
Date: Wed, 08 Jan 2003 20:20:21 GMT
If you familiar with how EOF works, it propagates object updates among
EOEditingContexts within the same JVM, but not accross JVMs. For me (and I
believe for others too) this was a source of many problems.
So at the early design stages we made a deliberate decision to exclude
update notifications from Cayenne, until we implement a mechanism that
handles it the same way for both local and remote DataContexts.
Now I hope the time is approaching when we are ready to start solving this
problem (see recent Holger's messages on cayenne-devel on this topic). This
is still in the design stage though... So current DataContext is always an
isolated view of the data.
Andrus
Dave Paules writes:
> Hi list,
> I was using Cayenne the other day and I didn't see an elegant way for
> recognizing when another user has made changes to the same object I have
> changed.
>
> Let's use an example:
>
> I have a Person entity with firstName and lastName attributes.
> The instance in question has the values "Dave" and "Paules" respectively.
>
> user1 and user2 have both fetched the Person instance Dave Paules.
> Let's say user1 changes the firstName attribute from "Dave" to "dave". He
> commits his change.
> Meanwhile user2 decides to change the lastName attribute from "Paules" to
> "PAULES".
>
> After committing his change to lastName, user2 will not see user1's
> firstName change once his commit has successfully completed. user2, even
> thought he was making changes to an object, and that object needs to be
> reconciled with the database (or at least the ObjectStore's snapshot), it is
> not.
>
> user2 believes after his commit that the Person has values "Dave" and
> "PAULES". In reality, the ObjectStore and the database have the correct
> values: "dave" and "PAULES".
>
> Why is user2's object not updated first from the ObjectStore's snapshot
> during a commit, and then his changes applied on top of this most recent
> view?
> Perhaps this cannot be done for toMany relationships, but it should be
> possible for 1:1 and local persistent attributes of the object.
>
> What are your thoughts? I think this automation is sorely missed in Cayenne.
> Does anyone know of a more elegant workaround? Any help is much appreciated.
>
> Thanks in advance
> Dave Paules
> Quantum Leap Innovations
> www.quantumleap.us
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