ios - テーブルに値を挿入しているときにコアデータが null 配列を返す理由

Question

私には2つの方法がありますが、

最初の方法では値を Core Data に保存しますが、他の方法では値を取得するだけです。

挿入後、同じメソッドでデータをフェッチすると値が表示されますが、他のメソッドでフェッチしようとするとnullが返されます。

私の節約方法は

-(void) saveloginData:(NSString *)facebookTok username:(NSString *)userName password:(NSString*)password flag:(NSString *)flag {


NSError *error;

NSManagedObjectContext *context = [self managedObjectContext];



NSFetchRequest * fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setEntity:[NSEntityDescription entityForName:@"SignIn" inManagedObjectContext:context]];
[fetchRequest setIncludesPropertyValues:NO]; //only fetch the managedObjectID

NSString *facebookTokenData = facebookTok;
NSString *usernameData = userName;
NSString *passwordData = password;
NSString *flagData = flag;


NSLog(@"Facebook Token%@\nUsername%@\npassword%@\nflat%@\n",facebookTokenData,usernameData,passwordData,flagData);


SignIn *signIn = [NSEntityDescription
                                        insertNewObjectForEntityForName:@"SignIn"
                                        inManagedObjectContext:context];

signIn.facebookToken = facebookTokenData;
signIn.username = usernameData;
signIn.password = passwordData;
signIn.flag = flagData;


NSEntityDescription *entity = [NSEntityDescription entityForName:@"SignIn"
                                          inManagedObjectContext:context];

[fetchRequest setEntity:entity];

NSArray *fetchedArray = [context executeFetchRequest:fetchRequest error:&error];


for (SignIn *info in fetchedArray) { 
            \\ THis executes and shows values, proves that value are inserted.

    NSLog(@"Name  ~~~~ : %@", info.username);
    NSLog(@"Password ~~~~~~~~ :%@", info.password);
    NSLog(@"FLAG ~~~~~~~~~~~ %@",info.flag);
    NSLog(@"Facebook Token %@", info.facebookToken);
}
}

私の取得方法は

-(NSArray*) getLoginData {

NSError *error;

NSManagedObjectContext *context = [self managedObjectContext];

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];

NSEntityDescription *entity = [NSEntityDescription entityForName:@"SignIn"
                                          inManagedObjectContext:context];


[fetchRequest setEntity:entity];

NSArray *fetchedData = [[NSArray alloc] init];


fetchedData = [context executeFetchRequest:fetchRequest error:&error];

NSLog(@"The count of Array %d", [fetchedData count]); \\ HERE COUNT IS ZERO, WHY?


for (SignIn *info in fetchedData) {
    NSLog(@" FF    Name  ~~~~ : %@", info.username);
    NSLog(@"Password ~~~~~~~~ :%@", info.password);
    NSLog(@"FLAG ~~~~~~~~~~~ %@",info.flag);
    NSLog(@"Facebook Token %@", info.facebookToken);
}


return fetchedData;
 }

私が間違っているところを案内してください。