小编bru*_*sas的帖子

我在添加关系后获取对象时遇到问题.我第一次获取类别,总是找到,然后当我添加到关系时,找不到以下类别.

这种关系是一种Many-To-Many.

例:

• 获取类别 categoryId = 10
• 找到类别对象
• 添加到父对象关系
• 下一个对象

• 如果几个类别相同id,则categoryId = 10找不到

  NSManagedObjectContext *private = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
  
     [private setParentContext:self.model.context];
      __block NSError *error = nil;
  
      [private performBlockAndWait:^{
  
          GPDeal *deal = [EKManagedObjectMapper objectFromExternalRepresentation:dic withMapping:[GPDeal objectMapping] inManagedObjectContext:private];
          for (NSDictionary *dic in responseObject[@"response"]) {
  
              GPCategory *category;
  
             //The first time always found
              if ((category = [GPCategory MR_findFirstByAttribute:@"catId" withValue:dic[@"mainAttribute"] inContext:private])) {
                  NSLog(@"Found");
                  [category addDealsObject:deal];
  
              } else {
                  NSLog(@"Not Found");
  
              }
  
          }
      }];
  
      NSError *PrivateError = nil;
      if (![private …

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