gistfile1.m

+ (NSManagedObject *)managedObjectFromStructure:(NSDictionary *)structureDictionary 
                                     entityName:(NSString *)entityName 
                       withManagedObjectContext:(NSManagedObjectContext *)context {
    
    NSMutableDictionary *mutableStructureDictionary = [structureDictionary mutableCopy];
    
    NSManagedObject *managedObject = [NSEntityDescription insertNewObjectForEntityForName:entityName 
                                                                   inManagedObjectContext:context];
    
    NSDictionary *relationshipsByName = [[managedObject entity] relationshipsByName];
    
    for (NSString *relationshipName in [relationshipsByName allKeys]) {
        NSRelationshipDescription *relationshipDescription = [relationshipsByName objectForKey:relationshipName];
        NSString *relationshipEntityName = [[relationshipDescription destinationEntity] name];
        
        if (![relationshipDescription isToMany]) {
            NSDictionary *childStructureDictionary = [mutableStructureDictionary objectForKey:relationshipName];
            NSManagedObject *childObject = [[self class] managedObjectFromStructure:childStructureDictionary 
                                                                         entityName:relationshipEntityName 
                                                           withManagedObjectContext:context];
            [managedObject setValue:childObject forKey:relationshipName];
        } else {
            NSMutableSet *relationshipSet = [managedObject mutableSetValueForKey:relationshipName];
            NSArray *relationshipArray = [mutableStructureDictionary objectForKey:relationshipName];
            
            for (NSDictionary *childStructureDictionary in relationshipArray) {
                NSManagedObject *childObject = [[self class] managedObjectFromStructure:childStructureDictionary 
                                                                             entityName:relationshipEntityName 
                                                               withManagedObjectContext:context];
                [relationshipSet addObject:childObject];
            }
        }
        
        [mutableStructureDictionary removeObjectForKey:relationshipName];
    }
    
    [managedObject setValuesForKeysWithDictionary:mutableStructureDictionary];
    
    [mutableStructureDictionary release];
    
    return managedObject;
}

and what is problem?

I'd like you just to check this code :)

The first mistake I've found is that I need to use entityName except of entityClassName. So this code wouldn't work if entityName differs from its className.

And also, there's no check if such entity already exist. And even more, I have no idea on what's the correct way to add it :)

ok, I'll review it today.