[Objective-C] CoreDataを使う ref: https://qiita.com/edo_m18/items/8bc7615eb2f6d546705d

AppDelegateSample.m

- (NSURL *)applicationDocumentsDirectory
{
    NSURL *url = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
    return url;
}

CoreDataSample-managedObjectContext.m

- (NSManagedObjectContext *)managedObjectContext
{
    if (_managedObjectContext != nil) {
        return _managedObjectContext;
    }

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (coordinator != nil) {
        _managedObjectContext = [[NSManagedObjectContext alloc] init];
        [_managedObjectContext setPersistentStoreCoordinator:coordinator];
    }

    return _managedObjectContext;
}

CoreDataSample-managedObjectModel.m

- (NSManagedObjectModel *)managedObjectModel
{
    if (_managedObjectModel != nil) {
        return _managedObjectModel;
    }

    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"HogeModel" withExtention:@"momd"];
    _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];

    return _managedObjectModel;
}

CoreDataSample-persistentStoreCoordinator.m

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    if (_persistentStoreCoordinator) {
        return _persistentStoreCoordinator;
    }

    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"HogeProj.splite"];

    NSError *error = nil;
    _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    if (![_persistentStoreCoordinator addPersistentStoreWitType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }

    return _persistentStoreCoordinator;
}

DeleteSample.m

//削除対象のフェッチ情報を生成
NSFetchRequest *deleteRequest = [[NSFetchRequest alloc] init];
[deleteRequest setEntity:[NSEntityDescription entityForName:@"HogeData" inManagedObjectContext:managedObjectContext]];
[deleteRequest setIncludesPropertyValues:NO]; //managed object IDのみフェッチ

NSError *error = nil;

//生成したフェッチ情報からデータをフェッチ
NSArray *results = [managedObjectContext executeFetchRequest:deleteRecest error:&error];
//[deleteRequest release]; //ARCオフの場合

//フェッチしたデータを削除処理
for (NSManagedObject *data in results) {
    [managedObjectContext deleteObject:data];
}

NSError *saveError = nil;

//削除を反映
[managedObjectContext save:&saveError];

fetchsample.m

//fetch設定を生成
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:NSStringFromClass([HogeData class])];

//sort条件を設定
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];

//ARCオフの場合はreleaseする
//[sortDescriptor release];
//[sortDescriptors release];

//fetch設定を元に、managedObjectContextからデータを取得
//返り値は`NSManagedObject`の配列になる
NSArray *results = [self.managedObjectContext executeFetchRequest:fetchRequest error:nil];

for (NSManagedObject *data in results) {
    //do something.
}

file0.m

- (NSManagedObjectModel *)managedObjectModel
{
    if (_managedObjectModel != nil) {
        return _managedObjectModel;
    }

    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"HogeModel" withExtension:@"momd"];
    _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];

    return _managedObjectModel;
}

file1.m

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    if (_persistentStoreCoordinator) {
        return _persistentStoreCoordinator;
    }

    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"HogeProj.splite"];

    NSError *error = nil;
    _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }

    return _persistentStoreCoordinator;
}

file2.m

- (NSManagedObjectContext *)managedObjectContext
{
    if (_managedObjectContext != nil) {
        return _managedObjectContext;
    }

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (coordinator != nil) {
        _managedObjectContext = [[NSManagedObjectContext alloc] init];
        [_managedObjectContext setPersistentStoreCoordinator:coordinator];
    }

    return _managedObjectContext;
}

file3.m

//fetch設定を生成
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:NSStringFromClass([HogeData class])];

//sort条件を設定
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];

//ARCオフの場合はreleaseする
//[sortDescriptor release];
//[sortDescriptors release];

//fetch設定を元に、managedObjectContextからデータを取得
//返り値は`NSManagedObject`の配列になる
NSArray *results = [self.managedObjectContext executeFetchRequest:fetchRequest error:nil];

for (NSManagedObject *data in results) {
    //do something.
}

file4.m

HogeData *hogeData = (HogeData *)[NSEntityDescription insertNewObjectForEntityForName:@"HogeData" inManagedObjectContext:managedObjectContext];

file5.m

//削除対象のフェッチ情報を生成
NSFetchRequest *deleteRequest = [[NSFetchRequest alloc] init];
[deleteRequest setEntity:[NSEntityDescription entityForName:@"HogeData" inManagedObjectContext:managedObjectContext]];
[deleteRequest setIncludesPropertyValues:NO]; //managed object IDのみフェッチ

NSError *error = nil;

//生成したフェッチ情報からデータをフェッチ
NSArray *results = [managedObjectContext executeFetchRequest:deleteRecest error:&error];
//[deleteRequest release]; //ARCオフの場合

//フェッチしたデータを削除処理
for (NSManagedObject *data in results) {
    [managedObjectContext deleteObject:data];
}

NSError *saveError = nil;

//削除を反映
[managedObjectContext save:&saveError];

file6.m

- (NSURL *)applicationDocumentsDirectory
{
    NSURL *url = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
    return url;
}

file7.m

// Entityを指定してFetchRequestを作る
NSFetchRequest *request = [[NSFetchRequest alloc] initWithEntityName:NSStringFromClassName(anEntityClass.class)];
request.includesSubentities = NO;

NSError *error = nil;

AppDelegate *delegate = UIApplication.sharedApplication.deleate;

// NSManagedObjectContextから、生成したリクエストを元に件数だけを取得
// （NSManagedObjectContextは適宜定義されているものに置き換えてください）
NSInteger count = [delegate.managedObjectContext countForFetchRequest:request error:&error];

// もし見つからなければ0件
if (count == NSNotFound) {
    return 0;
}

return count;

Sample.m

HogeData *hogeData = (HogeData *)[NSEntityDescription insertNewObjectForEntityForName:@"HogeData" inManagedObjectContext:managedObjectContext];