Question

I had spent few hours try to insert/add object but duplicated records happened. Campaign record re-inserted even it already exists. Am I missing something?

Below are my codes:

Campaign.h

@interface Campaign : NSManagedObject

@property (nonatomic, strong) NSNumber* campaignId;
@property (nonatomic, strong) NSString* title;

@end

Card.h

@class Campaign;

@interface Card : NSManagedObject

@property (nonatomic, strong) NSNumber* cardId;
@property (nonatomic, strong) NSString* name;
@property (nonatomic, strong) Campaign* campaign;

@end

ViewController.m

...

Campaign* campaign = [Campaign object];
campaign.campaignId = [NSNumber numberWithInt:1];
campaign.title = @"Hello world";

Card* card = [Card object];
card.cardId = @"1234567890";
card.campaign = campaign;

[[[RKObjectManager sharedManager] objectStore] save:nil];

EDITED ViewController.m

...
RKManagedObjectMapping* cardMapping = [RKManagedObjectMapping mappingForClass:[Card class] inManagedObjectStore:[RKObjectManager sharedManager].objectStore];
[cardMapping mapKeyPath:@"id" toAttribute:@"cardId"];
[campaignMapping mapKeyPath:@"name" toAttribute:@"name"];
cardMapping.primaryKeyAttribute = @"cardId";

RKManagedObjectMapping* campaignMapping = [RKManagedObjectMapping mappingForClass:[Campaign class] inManagedObjectStore:[RKObjectManager sharedManager].objectStore];
[campaignMapping mapKeyPath:@"id" toAttribute:@"campaignId"];
[campaignMapping mapKeyPath:@"title" toAttribute:@"title"];
campaignMapping.primaryKeyAttribute = @"campaignId";

Campaign* campaign = [Campaign object];
campaign.campaignId = [NSNumber numberWithInt:1];
campaign.title = @"Hello world";

Card* card = [Card object];
card.cardId = @"1234567890";
card.campaign = campaign;

[[[RKObjectManager sharedManager] objectStore] save:nil];

Answer 1

Yes, add a .primaryKeyAttribute to your mapping.
This will do the pk stuff for you when you are importing data via rest kit. If you are just doing ‘normal’ core data stuff with Restkit, you need to deal with referential integtrity etc. yourself.