I have two entities, Person and Notes, that have a one to many relationship. They both are NSManagedObjects. I believe I followed everything right from the Data Store and Core Data guides.

The problem: Whenever I try and save a person, it gives me "Reference object does not have ID set". From my understanding, person.notes is what it's referring to. But this should work according to the guides.

The code:

Person.m

- (NSDictionary *)hostToKinveyPropertyMapping {
    return @{
             @"entityId" : KCSEntityKeyId, //the required _id field
             //@"objectID" : @"objectID",
             //@"meta" : KCSEntityKeyMetadata,
             @"name" : @"name",
             @"initials" : @"initials",
             @"notes" : @"notes",
             };
}

+ (NSDictionary *)kinveyPropertyToCollectionMapping {
    return @{
             @"notes" : @"Notes",
             };
}

+(NSDictionary *)kinveyObjectBuilderOptions {
    // reference class map - maps properties to objects
    return @{ KCS_USE_DESIGNATED_INITIALIZER_MAPPING_KEY : @YES,
              KCS_REFERENCE_MAP_KEY : @{
                                        @"notes" : [MONotes class],
                                        }
              };
}

- (NSArray *)referenceKinveyPropertiesOfObjectsToSave {
    return @[ @"notes"];
}

+ (id)kinveyDesignatedInitializer:(NSDictionary *)jsonDocument
{
    NSString* existingID = jsonDocument[KCSEntityKeyId];
    id obj = nil;
    NSManagedObjectContext* context = defaultManagedObjectContext();
    NSEntityDescription* entity = [NSEntityDescription entityForName:@"Person" inManagedObjectContext:context];
    
    if (existingID) {
        NSFetchRequest *request = [[NSFetchRequest alloc] init];
        [request setEntity:entity];
        NSPredicate *predicate = [NSPredicate predicateWithFormat:@"entityId = %@", existingID];
        [request setPredicate:predicate];
        NSArray* results = [context executeFetchRequest:request error:NULL];
        if (results != nil && results.count > 0) {
            obj = results[0];
        }
    }
    
    if (obj == nil) {
        //fall back to creating a new if one if there is an error, or if it is new
        obj = [[MOPerson alloc] initWithEntity:entity insertIntoManagedObjectContext:context];
    }
    
    return obj;
}

Notes.m

- (NSDictionary *)hostToKinveyPropertyMapping {
    return @{
             @"entityId" : KCSEntityKeyId, //the required _id field
             //@"meta" : KCSEntityKeyMetadata, //meta maps to metadata
             @"dateAdded" : @"dateAdded",
             @"text" : @"text",
             @"person" : @"person"
             };
}

+ (NSDictionary *)kinveyPropertyToCollectionMapping
{
    return @{@"person" : @"Person"};
}

+(NSDictionary *)kinveyObjectBuilderOptions {
    // reference class map - maps properties to objects
    return @{ KCS_USE_DESIGNATED_INITIALIZER_MAPPING_KEY : @YES,
              KCS_REFERENCE_MAP_KEY : @{@"person" : [MOPerson class]
                                        }
              };
}

+ (id)kinveyDesignatedInitializer:(NSDictionary *)jsonDocument
{
    NSString* existingID = jsonDocument[KCSEntityKeyId];
    id obj = nil;
    NSManagedObjectContext* context = defaultManagedObjectContext();
    NSEntityDescription* entity = [NSEntityDescription entityForName:@"Notes" inManagedObjectContext:context];
    
    if (existingID) {
        NSFetchRequest *request = [[NSFetchRequest alloc] init];
        [request setEntity:entity];
        NSPredicate *predicate = [NSPredicate predicateWithFormat:@"entityId = %@", existingID];
        [request setPredicate:predicate];
        NSArray* results = [context executeFetchRequest:request error:NULL];
        if (results != nil && results.count > 0) {
            obj = results[0];
        }
    }
    
    if (obj == nil) {
        //fall back to creating a new if one if there is an error, or if it is new
        obj = [[MONotes alloc] initWithEntity:entity insertIntoManagedObjectContext:context];
    }
    
    return obj;
}

Thanks for the help!

Unfortunately not due to the fact that we are trying to reduce as much data used as possible. One theory is having a default value and then deleting it once it's successfully saved. But I'm querying all the data to update it and then I would have to iterate through all the data and delete each oneToOne entity that equals the default value.

Pranav,

Same issue as the initial problem. But it now works for one to many relationships. If add a one to one relationships it gives me: CoreData: error: Failed to call designated initializer on NSManagedObject class (was doing this for one to many relationships before the update).

 Snippet in onPostFetch:  

for (var i = 0; i < count; i++) {
    //oneToOne is the entity
    response.body[i].oneToOne = nil; // Try number 1, didn't like setting nil to the oneToOne for CoreData. Gave the same error in CoreData if I didn't change it.
    response.body[i].oneToOne = []; // Try number 2, array can't initialize oneToOne from NSArray
}

Not sure what to make oneToOne if it's nil or there's nothing.

Everything seems to be working except for fetching one to one relationships. If one entity is null, it cannot initialize the NSManagedObject. I've tried different ways of removing the null object in collection hooks, but Kinvey SDK still wants to initialize the object. I'm guessing it has to deal with - (NSDictionary *)hostToKinveyPropertyMapping; ?

Pranav,

Any progress or, hopefully, success?

Thanks,

Brian

Pranav,

That is correct. I am also getting the same crash.

Where/who can I send the project? The attach a file only lets me attach one file.