CoreData取数据提示data:且数据为空解决办法

/* Returns/sets if the objects resulting from a fetch request are faults.  If the value is set to NO, the returned objects are pre-populated with their property values (making them fully-faulted objects, which will immediately return NO if sent the -isFault message.)  If the value is set to YES, the returned objects are not pre-populated (and will receive a -didFireFault message when the properties are accessed the first time.)  This setting is not utilized if the result type of the request is NSManagedObjectIDResultType, as object IDs do not have property values.  Defaults to YES. 
*/
@property (nonatomic) BOOL returnsObjectsAsFaults NS_AVAILABLE(10_5,3_0);/* Returns/sets if the objects resulting from a