nsmanagedobjectcontext

I have a core-data entity with several attributes, and I want a list of all the objects in one attribute. My code looks like this: let appDel:AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate let context:NSManagedObjectContext = appDel.managedObjectContext! let sortDesc = NSSortDescriptor(key: "username", ascending: true) let fetchReq = NSFetchRequest(entityName: "Identities") fetchReq.sortDescriptors = [sortDesc] fetchReq.valueForKey("username") let en = NSEntityDescription.entityForName("Identities", inManagedObjectContext: context) userList = context

I have what I assume is a fairly standard setup, with one scratchpad MOC which is never saved (containing a bunch of objects downloaded from the web) and another permanent MOC which persists objects. When the user selects an object from scratchMOC to add to her library, I want to either 1) remove the object from scratchMOC and insert into permanentMOC, or 2) copy the object into permanentMOC. The Core Data FAQ says I can copy an object like this: NSManagedObjectID *objectID = [managedObject objectID]; NSManagedObject *copy = [context2 objectWithID:objectID]; (In this case, context2 would be

Question : How do I get my child context to see changes persisted on the parent context so that they trigger my NSFetchedResultsController to update the UI? Here's the setup: You've got an app that downloads and adds lots of XML data (about 2 million records, each roughly the size of a normal paragraph of text) The .sqlite file becomes about 500 MB in size. Adding this content into Core Data takes time, but you want the user to be able to use the app while the data loads into the data store incrementally. It's got to be invisible and imperceptible to the user that large amounts of data are

My app sometimes inserts objects into the managed object context that are not meant to necessarily be saved. For example, when I launch an 'add entity' modal, I create a managed object and assign it to the modal. If the user saves from that modal, I save the context. If he cancels, I delete the object and no save is necessary. I have now introduced an 'import' feature that switches to my app (using a URL scheme) and adds an entity. Because one of these modals might be open, it is not safe to save the context at this point. The transient object created for the modal will be saved, even if the

I have an app with two managed object contexts setup like this: Parent Context: NSPrivateQueueConcurrencyType, linked to the persistent store. Main Context: NSMainQueueConcurrencyType, child of Parent Context. When insert a new managed object to the main context, I save the main context and then the parent context like this: [context performBlockAndWait:^{ NSError * error = nil; if (![context save: &error]) { NSLog(@"Core Data save error %@, %@", error, [error userInfo]); } }]; [parentContext performBlock:^{ NSError *error = nil; BOOL result = [parentContext save: &error]; if ( ! result ) {