title: CoreData usage in Objective C
body: <p>When I use CoreData, use method <code>addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:url options:options error:&amp;error</code> to add a DataBase 1, switch user and login, add a DataBase 2, when I write data in DataBase2 but it's still writing in dataBase1, so how to change sqlite file in current <code>NSManagedObjectContext</code>?</p>