我保存时,我在CoreData上崩溃了:
2014-09-16 09:51:58.273 My_app[2678:105246] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString appendString:]: nil argument'
*** First throw call stack:
(
0 CoreFoundation 0x00000001087413f5 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x00000001083dabb7 objc_exception_throw + 45
2 CoreFoundation 0x000000010874132d +[NSException raise:format:] + 205
3 CoreFoundation 0x000000010871274f mutateError + 159
4 CoreData 0x000000010672ae56 -[_NSSQLGenerator prepareMasterReorderStatementPart2ForRelationship:] + 118
5 CoreData 0x0000000106792fd8 -[NSSQLAdapter newCorrelationMasterReorderStatementPart2ForRelationship:] + 72
6 CoreData 0x00000001067a9751 -[NSSQLiteConnection writeCorrelationMasterReordersFromTracker:] + 817
7 CoreData 0x00000001067aa061 -[NSSQLiteConnection writeCorrelationChangesFromTracker:] + 65
8 CoreData 0x000000010679c617 -[NSSQLCore …