Best way to implement Enums with Core Data

Question

What is the best way to bind Core Data entities to enum values so that I am able to assign a type property to the entity? In other words, I have an entity called Item<

Answer 1

Since enums are backed by a standard short you could also not use the NSNumber wrapper and set the property directly as a scalar value. Make sure to set the data type in the core data model as "Integer 32".

MyEntity.h

typedef enum {
kEnumThing, /* 0 is implied */
kEnumWidget, /* 1 is implied */
} MyThingAMaBobs;

@interface myEntity : NSManagedObject

@property (nonatomic) int32_t coreDataEnumStorage;

Elsewhere in code

myEntityInstance.coreDataEnumStorage = kEnumThing;

Or parsing from a JSON string or loading from a file

myEntityInstance.coreDataEnumStorage = [myStringOfAnInteger intValue];

Answer 2

An alternative approach I'm considering is not to declare an enum at all, but to instead declare the values as category methods on NSNumber.

Answer 3

I set the attribute type as 16 bit integer then use this:

#import <CoreData/CoreData.h>

enum {
    LDDirtyTypeRecord = 0,
    LDDirtyTypeAttachment
};
typedef int16_t LDDirtyType;

enum {
    LDDirtyActionInsert = 0,
    LDDirtyActionDelete
};
typedef int16_t LDDirtyAction;


@interface LDDirty : NSManagedObject

@property (nonatomic, strong) NSString* identifier;
@property (nonatomic) LDDirtyType type;
@property (nonatomic) LDDirtyAction action;

@end

...

#import "LDDirty.h"

@implementation LDDirty

@dynamic identifier;
@dynamic type;
@dynamic action;

@end