在核心数据中添加对象

Question

I am trying to get familiar with Core Data and had Xcode create subclasses of NSManagedObject for me. One is AddressAnnotation that just has some information about the location like street, zip, address, etc. The other is:

Map : NSManagedObject
@property (nonatomic, retain) NSString * name;
@property (nonatomic, retain) NSSet *locations;
- (void)addLocationsObject:(AddressAnnotation *)value;
- (void)removeLocationsObject:(AddressAnnotation *)value;
- (void)addLocations:(NSSet *)values;
- (void)removeLocations:(NSSet *)values;

When I want to add a location to the map, I do:

- (void)insertLocationIntoMap:(Map *)map {  
    [map addLocationsObject:self.address];

I NSLogged the Map object and the address object and both have values in it. When I try adding the object to an existing Map object, it does not seem to get added. The output of that map logged is:

<Map: 0x7087480> (entity: Map; id: 0x7084ff0 <x-coredata://8D6D7849-E7EC-48A3-BA95-C082D09E5D6D/Map/p1> ; data: {
    locations = "<relationship fault: 0x768e4e0 'locations'>";
    name = asdf;
})

If I create a new map, and then call insertLocationIntoMap:, the AddressAnnotation object does get added. That map logged is:

<Map: 0x767dee0> (entity: Map; id: 0x767d2d0 <x-coredata://8D6D7849-E7EC-48A3-BA95-C082D09E5D6D/Map/p5> ; data: {
    locations =     (
    );
    name = asdfasdf;
})

Am I doing something wrong in adding an AddressAnnotation to the Maps object? This was working when I didn't use subclasses of NSManagedObject and was just using setValue:forKey: everywhere, but I thought this would be more intuitive after I got used to it. Thanks!

Answer 1

The first log shows a fault for the relationship. This tells nothing about which objects are in that relationship. You should also log your AddressAnnotation.map relationship. Is it a one-to-many or a many-to-many relationship?

And ultimately, if you want to print out which objects are related, you should use a fetch request to fetch the objects in the locations relationship ( @"self.map == %@" for the AddressAnnotation entity with %@ substituted with the Map instance you are interested in).