Issue CoreData Migration - iphone

Question

I have an App with two sqlite databases and two xcdatamodel´s. So every things fine, except if i want to change or add some properties to one of the models.
I am creating a new model version and make my changes to that. After Setting the current model version, i start my app and get following Exception:
Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'This NSPersistentStoreCoordinator has no persistent stores. It cannot perform a save operation.'
I have the following Manager for my CoreData Operations:
#interface CoreDataManager ()
#property (strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;
#property (strong, nonatomic) NSManagedObjectModel *managedObjectModel;
#property (strong, nonatomic) NSManagedObjectContext *mainQueueContext;
#property (strong, nonatomic) NSManagedObjectContext *privateQueueContext;
#end
#implementation CoreDataManager
+ (instancetype)defaultStore
{
static CoreDataManager *_defaultStore = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
_defaultStore = [self new];
});
return _defaultStore;
}
#pragma mark - Singleton Access
+ (NSManagedObjectContext *)mainQueueContextWithDB:(NSString *)db
{
return [[self defaultStore] mainQueueContextWithDB:db];
}
+ (NSManagedObjectContext *)privateQueueContextWithDB:(NSString *)db
{
return [[self defaultStore] privateQueueContextWithDB:db];
}
+ (NSManagedObjectID *)managedObjectIDFromString:(NSString *)managedObjectIDString
{
return [[[self defaultStore] persistentStoreCoordinator] managedObjectIDForURIRepresentation:[NSURL URLWithString:managedObjectIDString]];
}
#pragma mark - Lifecycle
- (id)init
{
self = [super init];
if (self) {
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(contextDidSavePrivateQueueContext:)name:NSManagedObjectContextDidSaveNotification object:[self privateQueueContext]];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(contextDidSaveMainQueueContext:) name:NSManagedObjectContextDidSaveNotification object:[self mainQueueContext]];
}
return self;
}
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
#pragma mark - Notifications
- (void)contextDidSavePrivateQueueContext:(NSNotification *)notification
{
#synchronized(self) {
[self.mainQueueContext performBlock:^{
[self.mainQueueContext mergeChangesFromContextDidSaveNotification:notification];
}];
}
}
- (void)contextDidSaveMainQueueContext:(NSNotification *)notification
{
#synchronized(self) {
[self.privateQueueContext performBlock:^{
[self.privateQueueContext mergeChangesFromContextDidSaveNotification:notification];
}];
}
}
#pragma mark - Getters
- (NSManagedObjectContext *)mainQueueContextWithDB:(NSString *)db
{
actualDB = db;
if (!_mainQueueContext) {
_mainQueueContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
_mainQueueContext.persistentStoreCoordinator = self.persistentStoreCoordinator;
}
return _mainQueueContext;
}
- (NSManagedObjectContext *)privateQueueContextWithDB:(NSString *)db
{
actualDB = db;
if (!_privateQueueContext) {
_privateQueueContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
_privateQueueContext.persistentStoreCoordinator = self.persistentStoreCoordinator;
}
return _privateQueueContext;
}
#pragma mark - Stack Setup
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
if (!_persistentStoreCoordinator) {
_persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:self.managedObjectModel];
NSError *error = nil;
if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:[self persistentStoreURL] options:[self persistentStoreOptions] error:&error]) {
NSLog(#"Error adding persistent store. %#, %#", error, error.userInfo);
}
}
return _persistentStoreCoordinator;
}
- (NSManagedObjectModel *)managedObjectModel
{
if (_managedObjectModel != nil) {
return _managedObjectModel;
}
_managedObjectModel = [NSManagedObjectModel mergedModelFromBundles:nil];
return _managedObjectModel;
}
- (NSURL *)persistentStoreURL
{
return [[NSFileManager appLibraryDirectory] URLByAppendingPathComponent:actualDB];
}
- (NSDictionary *)persistentStoreOptions
{
return #{NSInferMappingModelAutomaticallyOption: #YES, NSMigratePersistentStoresAutomaticallyOption: #YES};
}
#end

Answer 1

You may try to change the journal_mode to DELETE (guess WAL is default in Core Data on iOS 7 and higher ?!?). The persistent store options which i use and having no trouble with dozens of data model changes is:
NSMutableDictionary *options = [NSMutableDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
[NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption,
#{#"journal_mode" : #"DELETE"}, NSSQLitePragmasOption, nil];
I hope it helps ...
About Journal Mode on http://www.sqlite.org/pragma.html:
"The DELETE journaling mode is the normal behavior. In the DELETE mode, the rollback journal is deleted at the conclusion of each transaction. Indeed, the delete operation is the action that causes the transaction to commit. (See the document titled Atomic Commit In SQLite for additional detail.)"