CoreData-不在NSSet上保存关系或外键详细信息

Question

I googled and looked at most of the Core data questions before deciding to post in SO. It's kind of weird and I don't know where to go from here.

I'm building an iOS app and I'm using RestKit, Core Data and Objective Record. Before I go into the details, note that my Object Context and Object Store for Objective Record and RKObjectManager are the same. So I'm not referring objects outside the same contexts.Enough intro..

Feed_Items model is the top one in the hierarchy.

--Feed_Items

------OutFit Model (1-to-1 / Optional )

------Clothe Model (1-t0-1 / Optional )

Both Clothe and Outfit have same set of attributes and I'm interested particularly in the 'comments' attribute

--Clothe / Outfit

------Other fields

------NSSet* Comments object

When I start the app, I load all the latest feeds from the server using RestKit(json) and Object-Mapping. On the first load, I get only 1 feed item which is an outfit and that outfit has a total of 7 comments of which 5 are loaded initially. So far so good and I get the Feed_Item object and the corresponding Outfit and the 5 comments in NSSet.

Now when the user wants to load all the previous comments, I invoke another API and it returns 2 new comments which is parsed successfully as Comment objects.

[objectManager getObjectsAtPath:[NSString stringWithFormat:@"api/outfit/comments/%d",[_feed.outfit.outfit_id intValue]]
             parameters:_params
                success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
                    for( Comment* _comment in [mappingResult array]){
                        [_feed.outfit addCommentsObject:_comment];
                        [_comment save];
                    }
                }
                failure:^(RKObjectRequestOperation *operation, NSError *error) {

                }];

There aren't any exceptions or errors however I suspect the foreign key for the last 2 Comment objects are not getting updated in the sqlite db. Please see the image below

To further prove my point, I tried the below on my second run

Outfit *_outfit = [[Outfit where:@"outfit_id == 3"] objectAtIndex:0];
NSLog(@"%@", [_outfit.comments allObjects]);

and there are only 5 obects

"<Comment: 0xc185ed0> (entity: Comment; id: 0xc185840 <x-coredata://2C61C98F-0B5F-4111-B681-1E43ABFB33D4/Comment/p6> ; data: <fault>)",
"<Comment: 0xc185c00> (entity: Comment; id: 0xc185820 <x-coredata://2C61C98F-0B5F-4111-B681-1E43ABFB33D4/Comment/p1> ; data: <fault>)",
"<Comment: 0xc185f10> (entity: Comment; id: 0xc185850 <x-coredata://2C61C98F-0B5F-4111-B681-1E43ABFB33D4/Comment/p8> ; data: <fault>)",
"<Comment: 0xc185f70> (entity: Comment; id: 0xc185860 <x-coredata://2C61C98F-0B5F-4111-B681-1E43ABFB33D4/Comment/p9> ; data: <fault>)",
"<Comment: 0xc185e90> (entity: Comment; id: 0xc185830 <x-coredata://2C61C98F-0B5F-4111-B681-1E43ABFB33D4/Comment/p4> ; data: <fault>)"

I don't know what happened to the last 2 objects and why it's not hooked up. It's successfully saved in the database as you can see from the image but looks like the relationship or the foreign key is not set. Any idea what's going wrong?

Cheers

Answer 1

For those who are using RestKit + Core Data + Objective Record, please ensure you modify the saveTheContext method in NSManagedObject+ActiveRecord.m like the following.

- (BOOL)saveTheContext {
    if (self.managedObjectContext == nil ||
        ![self.managedObjectContext hasChanges]) return YES;

    NSError *error = nil;
    BOOL save = [self.managedObjectContext saveToPersistentStore:&error];
    if (!save || error) {
        NSLog(@"Unresolved error in saving context for entity:\n%@!\nError: %@", self, error);
        return NO;
    }

    return YES;
} 

Key to note here is the call to saveToPersistentStore which is an RKAdditions category on NSManagedObjectContext. Without this RestKit initialized object won't save any changes in the persistent store.

It took me a day to figure this out.