RestKit Object Mapping relationships with foreign keys

Question

Can RestKit connect a relationship without storing the foreign key as an attribute, i.e., directly from the keypath in the JSON? In particular, I've got a Job has_many Rooms relationship. The room's JSON doesn't contain the job, rather, both are loaded separately: ``` - job: { id: 1, name: "John" } - room: { id: 4, job_id: 1, name: "spare bedroom" } ``` The Job is loaded before the Room. My CoreData models, Job has properties for ``` @interface Job : NSManagedObject @property (nonatomic, retain) NSNumber * identifier; @property (nonatomic, retain) NSString * name; @property (nonatomic, retain) NSSet *rooms; @end @interface Room : NSManagedObject @property (nonatomic, retain) NSNumber * identifier; @property (nonatomic, retain) NSString * name; @property (nonatomic, retain) Job *job; @end ``` Currently I add a `@property (nonatomic, strong) NSNumber *jobID;` to Room, which I `@synthesize`. ``` JobMapping: mapping = [RKManagedObjectMapping mappingForClass:[Job class]]; [mapping setPrima…

Accepted Answer

I would make JobId a transient value in core data, and write a custom set and get for it.

The set would set the relationship to self.job=methodToReturnObjectMatchingJobId (this would be used by rest kit)

The get would return self.job.identifier

If you are not using mogenerator, I would suggest you have a look at it for all your core data needs.

Below is sample code of how i did it:

```
-(void) setClaimId:(NSNumber *)claimId{
     Claim *propertyClaim=[Claim listItemFromId:[claimId intValue] withContext:self.managedObjectContext];

self.claim=propertyClaim; 
}
-(NSNumber*) claimId{

return self.claim.referenceId;
}
```

where listItemFromId is a simple query that returns the object based on the id.

RestKit Object Mapping relationships with foreign keys

Solution

Problem