在iPhone上学习核心数据.关于核心数据用节填充表视图的示例似乎很少.CoreDataBooks示例使用部分，但它们是从模型中的完整字符串生成的.我想按姓氏的第一个字母(如地址簿)将核心数据表组织成多个部分.
我可以进go for each 人创建另一个属性，即一个字母，作为分区，但这似乎很难.
这就是我要开始的...诀窍似乎是在愚弄这sectionNameKeyPath人:
- (NSFetchedResultsController *)fetchedResultsController {
//.........SOME STUFF DELETED
// Edit the sort key as appropriate.
NSSortDescriptor *orderDescriptor = [[NSSortDescriptor alloc] initWithKey:@"personName" ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:orderDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
// Edit the section name key path and cache name if appropriate.
// nil for section name key path means "no sections".
NSFetchedResultsController *aFetchedResultsController =
[[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
managedObjectContext:managedObjectContext
sectionNameKeyPath:@"personName" cacheName:@"Root"];
//....
}