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当我尝试在iPhone Core-Data应用程序的列上获取@sum时,发生异常。核心数据@sum聚合
我的两个模型如下 -
任务模式:
@interface Task : NSManagedObject
{
}
@property (nonatomic, retain) NSString * taskName;
@property (nonatomic, retain) NSSet* completion;
@end
@interface Task (CoreDataGeneratedAccessors)
- (void)addCompletionObject:(NSManagedObject *)value;
- (void)removeCompletionObject:(NSManagedObject *)value;
- (void)addCompletion:(NSSet *)value;
- (void)removeCompletion:(NSSet *)value;
@end
完成方式:
@interface Completion : NSManagedObject
{
}
@property (nonatomic, retain) NSNumber * percentage;
@property (nonatomic, retain) NSDate * time;
@property (nonatomic, retain) Task * task;
@end
这里是获取:
NSFetchRequest *request = [[NSFetchRequest alloc] init];
request.entity = [NSEntityDescription entityForName:@"Task" inManagedObjectContext:context];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"taskName" ascending:YES];
request.sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
NSError *error;
NSArray *results = [context executeFetchRequest:request error:&error];
NSArray *parents = [results valueForKeyPath:@"taskName"];
NSArray *children = [results valueForKeyPath:@"[email protected]"];
NSLog(@"%@ %@", parents, children);
[request release];
[sortDescriptor release];
唯一的例外是抛出从底部开始的第四行。被抛出的异常是:
*** -[NSCFSet decimalValue]: unrecognized selector sent to instance 0x3b25a30
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSCFSet decimalValue]: unrecognized selector sent to instance 0x3b25a30'
我将非常感谢任何形式的帮助。 谢谢。
编辑:我在雪豹10.6.3和SDK 3.1.3上。