Creating Core Data Entity working but fetching an Entity doesn't work - ios

Question

So, I have a `NSManagedObject's User, Boundary, and Preset. A Preset is always tied to a single user. A user can have many Presets. Each Preset may be tied a boundary.
Basicly, the User has a Preset that he can save to each Boundary he has.
User has a to-many relationship to Preset.
Boundary has a many-to-many relationship to Preset.
I am trying to generate a list of Presets that the User has minus the ones already tied to the boundary.
I am using Magical Records.
My issue is when I create a new User and Boundary, this works:
Boundary *boundary = [Boundary MR_createEntity];
boundary.name = #"test boundary";
UserDB *user = [UserDB MR_createEntity];
user.username = #"test User";
Preset *preset01 = [Preset MR_findFirstByAttribute:#"nameDisplay" withValue:#"C4"];
DLog(#"preset01.nameDisplay: %#", preset01.nameDisplay);
Preset *preset02 = [Preset MR_findFirstByAttribute:#"nameDisplay" withValue:#"B"];
DLog(#"preset02.nameDisplay: %#", preset02.nameDisplay);
[boundary setPresets:[NSSet setWithObject:preset01]];
[user setPresets:[NSSet setWithObjects:preset01, preset02, nil]];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"user == %# AND boundary != %#", user, boundary];
NSArray *presetsList = [Preset MR_findAllWithPredicate:predicate];
DLog(#"presetsList: %#", presetsList);
So I set preset01 to the boundary. I set preset01 and preset02 to the user. So I need a list that shows preset02 to the user (since preset01 is already tied to the boundary, the user shouldn't be able to add it again).
DEBUG | -[LoginViewController viewDidLoad] | preset01.nameDisplay: C4
DEBUG | -[LoginViewController viewDidLoad] | preset02.nameDisplay: B
DEBUG | -[LoginViewController viewDidLoad] | presetList: (
"<SoilTestPointPreset: 0x1e06b8b0> (entity: Preset; id: 0x1e06bca0 <x-coredata://7476DB86-AF79-445C-B3AE-6C91088704A0/Preset/p98> ; data: {\n attributes = \"<relationship fault: 0x1e074000 'attributes'>\";\n boundary = nil;\n gpsLocation = nil;\n nameDisplay = B;\n nameTitle = nil;\n rgbColor = \"0x1e06b1d0 <x-coredata://7476DB86-AF79-445C-B3AE-6C91088704A0/RGBColor/p49>\";\n testing = nil;\n user = \"0x1e05ff60 <x-coredata:///UserDB/t59757D99-2FBF-4FBF-97AF-39582FC4B5503>\";\n})"
)
Thats what I expected. But now when I fetch the User and Boundary objects:
Boundary *boundary = [Boundary MR_findFirstByAttribute:#"boundaryID" withValue:#3748];
DLog(#"boundary.name: %#", boundary.name);
UserDB *user = [UserDB MR_findFirstByAttribute:#"uid" withValue:#99];
DLog(#"user.username: %#", user.username);
My array is empty:
DEBUG | -[LoginViewController viewDidLoad] | boundary.name: 997677
DEBUG | -[LoginViewController viewDidLoad] | user.username: thatPerson
DEBUG | -[LoginViewController viewDidLoad] | preset01.nameDisplay: C4
DEBUG | -[LoginViewController viewDidLoad] | preset02.nameDisplay: B
DEBUG | -[LoginViewController viewDidLoad] | presetList: (
)
Why does fetching the User and Boundary from Core Data change the results as opposed to creating them?
UPDATE:
I added:
Boundary *boundary = [Boundary MR_findFirstByAttribute:#"boundaryID" withValue:#3748];
DLog(#"boundary.name: %#", boundary.name);
DLog(#"boundary.presets.count: %d", boundary.presets.count); // Added
UserDB *user = [UserDB MR_findFirstByAttribute:AVI_UID withValue:#99];
DLog(#"user.username: %#", user.username);
DLog(#"user.presets.count: %d", user.presets.count); // Added
DLog(#"AFTER | boundary.presets.count: %d", boundary.presets.count); //Added
DLog(#"AFTER | user.presets.count: %d", user.presets.count); //Added
[[NSManagedObjectContext MR_contextForCurrentThread] MR_saveToPersistentStoreAndWait]; //Added
They User and Boundary have Presets relationships:
DEBUG | -[LoginViewController viewDidLoad] | boundary.name: 997677
DEBUG | -[LoginViewController viewDidLoad] | BEFORE | boundary.presets.count: 0
DEBUG | -[LoginViewController viewDidLoad] | user.username: iDealer
DEBUG | -[LoginViewController viewDidLoad] | BEFORE | user.presets.count: 0
DEBUG | -[LoginViewController viewDidLoad] | preset01.nameDisplay: C4
DEBUG | -[LoginViewController viewDidLoad] | preset02.nameDisplay: B
DEBUG | -[LoginViewController viewDidLoad] | AFTER | boundary.presets.count: 1
DEBUG | -[LoginViewController viewDidLoad] | AFTER | user.presets.count: 2
-[NSManagedObjectContext(MagicalSaves) MR_saveWithOptions:completion:](0x20831a80) → Saving <NSManagedObjectContext (0x20831a80): *** DEFAULT ***> on *** MAIN THREAD ***
-[NSManagedObjectContext(MagicalSaves) MR_saveWithOptions:completion:](0x20831a80) → Save Parents? 1
-[NSManagedObjectContext(MagicalSaves) MR_saveWithOptions:completion:](0x20831a80) → Save Synchronously? 1
-[NSManagedObjectContext(MagicalSaves) MR_saveWithOptions:completion:](0x1f59e860) → Saving <NSManagedObjectContext (0x1f59e860): *** BACKGROUND SAVING (ROOT) ***> on *** MAIN THREAD ***
-[NSManagedObjectContext(MagicalSaves) MR_saveWithOptions:completion:](0x1f59e860) → Save Parents? 0
-[NSManagedObjectContext(MagicalSaves) MR_saveWithOptions:completion:](0x1f59e860) → Save Synchronously? 1
__70-[NSManagedObjectContext(MagicalSaves) MR_saveWithOptions:completion:]_block_invoke21(0x1f59e860) → Finished saving: <NSManagedObjectContext (0x1f59e860): *** BACKGROUND SAVING (ROOT) ***> on *** MAIN THREAD ***
DEBUG | -[LoginViewController viewDidLoad] | presetList: (
)

Answer 1

You need to save your data before you can fetch it from a store. Use MR_saveToPersistentStoreAndWait or other variants. Fetching always goes it 'disk', so saving first should fix this.

Answer 2

After a bunch of playing around, I narrowed down the issue to the NSPredicate I was using:
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"user == %# AND boundary != %#", user, boundary];
There seems to be an issue with NOT and NONE in the queries. Got the answer in a different question I post: NSPredicate with a !=?
The answer involves using a SUBQUERY instead of NOT.
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"user == %# AND SUBQUERY(boundary, $p, $p == %#).#count == 0", user, boundary];
I'm guessing the fetches I was making were fine, it would return 0 because of the bad NSPredicate, but I have not positive.