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POCoreData design pattern: persisting a single object of many -or-how many NSPessistentObjectContexts should I have?
 

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  1. POCoreData design pattern: persisting a single object of many -or-how many NSPessistentObjectContexts should I have?
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    <p>I'm converting an app from SQLitePersistentObjects to CoreData.</p> <p>In the app, have a class that I generate many* instances of from an XML file retrieved from my server. The UI can trigger actions that will require me to save <em>some</em>* of those objects until the next invocation of the app.</p> <p>Other than having a single NSManagedObjectContext for each of these objects (shared only with their subservient objects which can include blobs). I can't see a way how I can have fine grained control (i.e. at the object level) over which objects are persisted. If I try and have a single context for all newly created objects, I get an exception when I try to move one of my objects to a new context so I can persist it on ots own. I'm guessing this is because the objects it owns are left in the 'old' context.</p> <p>The other option I see is to have a single context, persist all my objects and then delete the ones I don't need later - this feels like it's going to be hitting the database too much but maybe CoreData does magic.</p> <p>So:</p> <ol> <li>Am I missing something basic about the way my CoreData app should be architected?</li> <li>Is having a context per object a good design pattern?</li> <li>Is there a better way to move objects between contexts to avoid 2?</li> </ol> <p>* where "many" means "tens, maybe hundreds, not thousands" and "some" is at least one order of magnitude less than "many"</p> <p>Also <a href="https://devforums.apple.com/message/78787#78787" rel="nofollow noreferrer">cross posted to the Apple forums</a>.</p>
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