//首先是VC的初始化如下

   //生成fetch请求

   NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Team"];

   //添加排序方式

   NSSortDescriptor *zoneSort = [NSSortDescriptor sortDescriptorWithKey:@"qualifyingZone" ascending:YES];

   NSSortDescriptor *scoresort = [NSSortDescriptor sortDescriptorWithKey:@"wins" ascending:NO];

   NSSortDescriptor *nameSort = [NSSortDescriptor sortDescriptorWithKey:@"teamName" ascending:YES];

   fetchRequest.sortDescriptors = @[zoneSort, scoresort, nameSort];

   //初始化NSFetchedResultsController，并以qualifyingZone来分为N个section，添加名为worldCup的缓存

   self.fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.coreDataStack.context sectionNameKeyPath:@"qualifyingZone" cacheName:@"worldCup"];

   self.fetchedResultsController.delegate = self;

   [self.fetchedResultsController performFetch:nil];

 //下面是VC协议的实现，如第一个函数所见，VC与tableView有相对应的处理类型：Insert、Delete、Update、Move

 #pragma mark - NSFetchedResultsControllerDelegate

 - (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath {

   TeamCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];

   switch (type) {

     case NSFetchedResultsChangeInsert:

       [self.tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationAutomatic];

       break;

     case NSFetchedResultsChangeDelete:

       [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];

       break;

     case NSFetchedResultsChangeUpdate:

       [self configureCell:cell withIndexPath:indexPath];

       break;

     case NSFetchedResultsChangeMove:

       [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];

       [self.tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationAutomatic];

       break;

     default:

       break;

   }

 }

 //需要注意的一点是，要有下面对tableView的更新方法，否则会报错

 - (void)controllerWillChangeContent:(NSFetchedResultsController *)controller {

   [self.tableView beginUpdates];

 }

 - (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {

   [self.tableView endUpdates];

 }