ios – 核心数据：插入一对多关系

评论：

在餐厅：

如果你让xcode生成你的课程,它将如下所示：

Restaurant:
@interface Restaurant : NsmanagedObject
@property (nonatomic,strong) NSSet *user_reviews;   /* One to Many Relation to Review Entity*/

@interface Restaurant(CoreDataGeneratedAccessors)

- (void)adduser_reviewsObject:(Review *)value;
- (void)removeuser_reviewsObject:(Review *)value;
- (void)adduser_reviews:(NSSet *)value;
- (void)removeuser_reviews:(NSSet *)value;

@end

Review:
@interface Review : NsmanagedObject
@property (nonatomic,strong) User *user;
@property (nonatomic,strong) Restaurant *restaurant;
@end

你的电话将是：

NsmanagedObjectContext *context = [self managedObjectContext];
Restaurant *rest = [NSEntityDescription insertNewObjectForEntityForName:@"Restaurant" inManagedObjectContext:context];
rest.name = restaurant.name;

Review *rev = [NSEntityDescription insertNewObjectForEntityForName:@"Review" inManagedObjectContext:context];
rev.rating = @"1";
rev.review_text = @"nomnomnom";

[rest adduser_reviewsObject:rev];
// or rev.restaurant = restaurant; one of both is enought as far as I remember

// save your context

编辑

如果它必须是一个NSMutableArray,它不能是一个ralation.
那些总是NSSets(如果x到n)或目的地类.使用NSMutableArray具有集合和自动处理的优点.

但是如果你真的要存储在NSMutableArray中,我建议至少通过一个reviewID属性(唯一)来扩展你的Review类,并将NSMutableArray存储为可变形.

//Review:

@interface Review : NsmanagedObject
@property (nonatomic,strong) NSnumber *reviewID;
@end

//Restaurant.h:

@interface Restaurant : NsmanagedObject
@property (nonatomic,strong) NSSet *user_reviews; // Set of NSnumbers

- (void)adduser_reviewsObject:(Review *)value;
- (void)adduser_reviewsID:(NSnumber *)value;
- (void)removeuser_reviewsObject:(Review *)value;
- (void)adduser_reviews:(NSMutableArray *)value;
- (void)removeuser_reviews:(NSMutableArray *)value;

@end

//Restaurant.m:

- (void)adduser_reviewsObject:(Review *)value
{
    [self adduser_reviewsID:value.reviewID];
}

- (void)adduser_reviewsID:(NSnumber *)value
{
    if(![self.user_reviews containsObject:value];
        [self.user_reviews addObject:value];
}

- (void)removeuser_reviewsObject:(NSnumber *)value
{
    // follow upper logic and implement yourself
}

- (void)adduser_reviews:(NSMutableArray *)value
{
    // follow upper logic and implement yourself
}

- (void)removeuser_reviews:(NSMutableArray *)value
{
    // follow upper logic and implement yourself
}