4
我試圖根據名爲「name」的屬性從核心數據中提取實體。這裏是我的代碼:使用屬性搜索實體時的核心數據SubEntitiesByName
NSManagedObjectContext *context = [self managedObjectContext];
NSEntityDescription *vegetable = [NSEntityDescription insertNewObjectForEntityForName:@"Vegetable" inManagedObjectContext:context];
// get the vegetable using name
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSPredicate *predicate =
[NSPredicate predicateWithFormat:@"name == %@", myGardenViewModel.vegetable.name];
[request setEntity:vegetable];
[request setPredicate:predicate];
NSError *error;
NSArray *fetchedObjects = [self.managedObjectContext executeFetchRequest:request error:&error];
最後一行拋出以下異常:
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Vegetable subentitiesByName]: unrecognized selector sent to instance 0x6bbcdd0'
什麼想法?