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From Marco Schulze <Ma...@NightLabs.de>
Subject Re: makePersistent detached instance deleted on database
Date Thu, 09 Mar 2006 19:29:40 GMT
Craig L Russell wrote:
> Hi Jörg,
>
> Using detachment for replication is an interesting use case, and I'd  
> like to see more in-depth analysis of the issues that you encounter  
> once you've done with it.
>
> The use-case for detachment is long-running optimistic transactions,  
> as you have noted below. We did add makeTransient(Object,  
> useFetchPlan) as a way to disconnect objects from one datastore that  
> could be used with another, but I really doubt that we are going to  
> be able to incorporate into the JDO API all the policy algorithms  
> needed by a general-purpose replication scheme.
>
> Craig
Hello Craig,

thanks a lot for this hint! I thought the combination of 
makeTransient(...) + makePersistent(...) doesn't work, if some of the 
objects within the object graph already exist in the destination. Am I 
wrong with this thought? Will makePersistent(...) really overwrite 
objects that already exist and add objects that are missing in this 
case? If so, it's exactly what we need and we're happy. Of course, it's 
slightly more work (currently all clients - for both, replication and 
normal client usage - call the same EJB methods), but that's only a 
minor problem.

Best regards, Marco :-)

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