2014/10/15 下午 10:12:16
iphone Programming Glossary: objectwithidCore Data: UIManagedDocument or AppDelegate to setup core data stack? http://stackoverflow.com/questions/14876988/core-data-uimanageddocument-or-appdelegate-to-setup-core-data-stack 𦑩ass a managed object from one context another across thread boundaries you either Pass its object ID objectID and use objectWithID or existingObjectWithID error on the receiving managed object context. The corresponding managed objects must have been..
Illegal attempt to establish a relationship 'xyz' between objects in different contexts http://stackoverflow.com/questions/1554623/illegal-attempt-to-establish-a-relationship-xyz-between-objects-in-different-c owner get an owner in a different MOC owner mutableSetValueForKey @ books addObject owner.managedObjectContext objectWithID book objectID So what you're doing is actually fetching the Book into the same managed object context with owner . Keep..
Fetching Core Data in the background http://stackoverflow.com/questions/1733117/fetching-core-data-in-the-background so that you can then display the results you use the second context to fault in objects with those object IDs you use objectWithID to instantiate the object . It sounds like the BackgroundFetching sample application shows how to do this but I don't have..
http://stackoverflow.com/questions/2009399/cryptic-error-from-core-data-nsinvalidargumentexception-reason-referencedata6 copy over by ID. I.e. NSManagedObjectID objectID foo objectID FooClass newFoo FooClass threadManagedObjectContext objectWithID objectID retain When finished parsing you need to save the changes made to the thread's NSManagedObjectContext. You must..
core data - the primary key id of a row in the database http://stackoverflow.com/questions/4720182/core-data-the-primary-key-id-of-a-row-in-the-database managedObjectIDForURIRepresentation and then get the object from a managed object context with NSManagedObjectContext objectWithID . BUT You should keep in mind that Core Data is not an ORM. It is an object graph management framework . That is uses SQLite..
How to get Core Data object from specific Object ID? http://stackoverflow.com/questions/5035057/how-to-get-core-data-object-from-specific-object-id with similar seeming names that tripped me up. To help keep them straight here's what the other two do NSManagedObject objectWithID NSManagedObjectID objectID ...will create a fault object with the provided objectID whether or not such an object actually..
Core Data's NSPrivateQueueConcurrencyType and sharing objects between threads http://stackoverflow.com/questions/8637921/core-datas-nsprivatequeueconcurrencytype-and-sharing-objects-between-threads NSManagedObject mo in results NSManagedObjectID moid mo objectID mainMOC performBlock ^ NSManagedObject mainMO mainMOC objectWithID moid Do stuff with 'mainMO'. Be careful NOT to use 'mo'. This gets less confusing if you move the inner mainMOC performBlock..
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