将一个对象插入多个关系 - IOS核心数据

Question

我已经看到各种答案，帮助解释在一对多关系中添加记录，但我似乎无法为我的代码做出头或尾。

我有一个关系 - 国家有很多县

我正在将县添加到已经存在但似乎无法获得将县添加到国家关系的方法...

我的代码是：

@class Country, Property;

@interface County : NSManagedObject

@property (nonatomic, retain) NSNumber * id;
@property (nonatomic, retain) NSDate * last_server_update;
@property (nonatomic, retain) NSString * name;
@property (nonatomic, retain) Country *country;
@property (nonatomic, retain) NSSet *properties;
@end

@interface County (CoreDataGeneratedAccessors)

- (void)addPropertiesObject:(Property *)value;
- (void)removePropertiesObject:(Property *)value;
- (void)addProperties:(NSSet *)values;
- (void)removeProperties:(NSSet *)values;

@end

国家.h

@class County, Property;

@interface Country : NSManagedObject

@property (nonatomic, retain) NSNumber * id;
@property (nonatomic, retain) NSDate * last_server_update;
@property (nonatomic, retain) NSString * name;
@property (nonatomic, retain) NSSet *properties;
@property (nonatomic, retain) County *counties;
@end

@interface Country (CoreDataGeneratedAccessors)

- (void)addPropertiesObject:(Property *)value;
- (void)removePropertiesObject:(Property *)value;
- (void)addProperties:(NSSet *)values;
- (void)removeProperties:(NSSet *)values;

- (void)addCountiesObject:(County *)value;
- (void)removeCountiesObject:(County *)value;
- (void)addCounties:(NSSet *)values;
- (void)removeCounties:(NSSet *)values;

@end

在我的控制器中：

Country * newCounty;
newCounty = [County createEntity];

// Get Country
Country * relatedCountry = [Country findFirstByAttribute:@"id" withValue:[county objectForKey:@"country_id"]];
                 
newCounty.id = [county objectForKey:@"id"];
newCounty.name = [county objectForKey:@"name"];
newCounty.country = relatedCountry;  // Does not compile

顺便说一句，我正在使用 MagicalRecord 作为查找器

编辑

错误 在“国家”类型的对象上找不到属性“国家”

关系设置为

国家

• 关系：县
• 目的地：县
• 逆向：国家
• 多对多关系：选中

县

• 关系：国家/地区
• 目的地：国家
• 逆：县
• 多对多关系：未选中

Answer 1

尝试改变

Country * newCounty;

到

County * newCounty;

;)