Core data attribute not being made

Question

I've decided to add an NSNumber attribute to one of my entities in core data. I Cleaned the code and deleted the app from the simulator. I then added the following code in my appDelegate and it tells me that my NSNumber attribute doesn't exist.

People *PeopleA = [NSEntityDescription insertNewObjectForEntityForName:@"People" inManagedObjectContext:context];
PeopleA.name = @"Paul";
PeopleA.number = [NSNumber numberWithInt:12];

The name attribute works just fine, that was made before and it's always worked. But when it gets to PeopleA.number it crashes with :

-[People setNumber:]: unrecognized selector sent to instance 0x4d5eeb0

So I did a po 0x4d5eeb0 and saw that there is a name attribute but not one for number. My core data class should be good because I had XCode make it for me.

What could possibly be the issue?

Here is my People.h

#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>

@class Group;

@interface People : NSManagedObject {
@private
}
@property (nonatomic, retain) NSString * name;
@property (nonatomic, retain) id image;
@property (nonatomic, retain) NSNumber * number;
@property (nonatomic, retain) Group * group;

@end

People.m

#import "People.h"
#import "Group.h"

@implementation People
@dynamic name;
@dynamic image;
@dynamic number;
@dynamic group;

@end

po 0x4d5eeb0 gets me:

<People: 0x5932290> (entity: People; id: 0x59322f0 <x-coredata:///People/t83A9C7D9-4F7A-4189-9EC5-7695968A29552> ; data: {
    group = nil;
    name = Paul;

did you synthesized your number property in People.m file? Do you have @dynamic number;? — akashivskyy
Yes, that's the only reason it got created in People.h and People.m. XCode made those files because number is an attribute. — tazboy
OK, I thought you might have edited those files by hand rather than having Xcode re-create them. — Tom Harrington

TechZen TechZen · Accepted Answer · 2011-07-06T22:08:33

Printing the object in the debugger should give you all the properties defined in the class regardless of whether it is a NSManagedObject subclass held by a context or just a plain vanilla custom class. The debugger printout is not only missing the number property but the image one as well.

Really, the only way that could happen was if you didn't have the new version of the class file added to the target but were actually using the old version that lacked the new properties.

Check the target for the old files and/or check that the new version has been properly added to the build target.

Core data attribute not being made

3 Answers