Could not delete core data PersistentStore - objective-c

Question

I want to remove the app PersistentStore completely. I read the following question completely and none of them worked:
Delete/Reset all entries in Core Data?
I have a Model Helper and do the delete task inside it:
#import <CoreData/CoreData.h>
#interface GeneralModel : NSFetchedResultsController
#property (nonatomic, strong) NSManagedObjectContext *context;
#property (nonatomic, strong) NSManagedObjectModel *model;
- (NSString *)storagePath;
- (void)removeStorage;
- (void)removeStorage2;
#end
#implementation GeneralModel
- (instancetype)init
{
self = [super init];
if (self) {
// Read in Model.xcdatamodeld
_model = [NSManagedObjectModel mergedModelFromBundles:nil];
NSPersistentStoreCoordinator *psc =
[[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:_model];
// Where does the SQLite file go?
NSString *path = self.storagePath;
NSURL *storeURL = [NSURL fileURLWithPath:path];
NSError *error = nil;
if (![psc addPersistentStoreWithType:NSSQLiteStoreType
configuration:nil
URL:storeURL
options:nil
error:&error]) {
#throw [NSException exceptionWithName:#"OpenFailure"
reason:[error localizedDescription]
userInfo:nil];
}
// Create the managed object context
_context = [[NSManagedObjectContext alloc] init];
_context.persistentStoreCoordinator = psc;
}
return self;
}
- (NSString *)storagePath
{
NSArray *documentDirectories =
NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
NSUserDomainMask,
YES);
// Get one and only document directory from that list
NSString *documentDirectory = [documentDirectories firstObject];
return [documentDirectory stringByAppendingPathComponent:#"model.sqlite"];
}
- (void)removeStorage {
NSPersistentStore *store = [self.context.persistentStoreCoordinator.persistentStores lastObject];
NSError *error = nil;
NSURL *storeURL = store.URL;
BOOL isRemovePersistentStore = [self.context.persistentStoreCoordinator removePersistentStore:store error:&error];
if (isRemovePersistentStore == NO) {
NSLog(#"NO RemovePersistentStore. Reason: %#", error.localizedFailureReason);
}
BOOL isRemoveItemAtURL = [[NSFileManager defaultManager] removeItemAtURL:storeURL error:&error];
if (isRemoveItemAtURL == NO) {
NSLog(#"NO RemoveItemAtURL. Reason: %#", error.localizedFailureReason);
}
}
- (void)removeStorage2 {
NSError *error;
NSString *storagePath = [self storagePath];
NSDictionary *options = #{NSPersistentStoreUbiquitousContentNameKey: #"model"};
bool removeResult = [NSPersistentStoreCoordinator removeUbiquitousContentAndPersistentStoreAtURL:[NSURL URLWithString:storagePath] options:options error:&error];
if (removeResult == NO) {
NSLog(#"Could not remove Storage. Reason: %#", error.localizedFailureReason);
}
}
#end
When I call the "removeStorage" method by the following code:
GeneralModel *model = [[GeneralModel alloc] init];
[model removeStorage];
Result is that No error apear in the console, but it just removed the main storage file: "model.sqlite" and 2 other related files: "model.sqlite-shm" and "model.sqlite-wal" remained.
When I call the "removeStorage2" method by the same code, I see the following text on the console and none of the files deleted:
Could not remove Storage. Reason: (null)
How could I solve this problem?

Answer 1

Check out the video "Straight outta Moscone Center West" for the official introduction of how you should be doing this, and/or consult NSPersistentStoreCoordinator.h from which the following snippet was extracted.
/* delete or truncate the target persistent store in accordance with the store
class's requirements. It is important to pass similar options as
addPersistentStoreWithType: ... SQLite stores will honor file locks, journal
files, journaling modes, and other intricacies. It is not possible to unlink
a database file safely out from underneath another thread or process, so this
API performs a truncation. Other stores will default to using NSFileManager.
*/
- (BOOL)destroyPersistentStoreAtURL:(NSURL *)url
withType:(NSString *)storeType
options:(nullable NSDictionary *)options
error:(NSError**)error NS_AVAILABLE(10_11, 9_0);
/* copy or overwrite the target persistent store in accordance with the store
class's requirements. It is important to pass similar options as
addPersistentStoreWithType: ... SQLite stores will honor file locks, journal
files, journaling modes, and other intricacies. Other stores will default
to using NSFileManager.
*/
- (BOOL)replacePersistentStoreAtURL:(NSURL *)destinationURL
destinationOptions:(nullable NSDictionary *)destinationOptions
withPersistentStoreFromURL:(NSURL *)sourceURL
sourceOptions:(nullable NSDictionary *)sourceOptions
storeType:(NSString *)storeType
error:(NSError**)error NS_AVAILABLE(10_11, 9_0);