我正在搜索，需要加快速度。我有一系列汽车零件，我想找到有这些零件的汽车。这部分我做得很好。NSManagedObject Cars.h
（汽车有一个名为 ToCarParts 的 NSSet，它列出了汽车的所有汽车零件）
NSMagagedObject Parts.h（Parts 有一个名为 ToCars 的 NSSet，它列出了与此关联的所有汽车）
//This takes all results gathered by using parts to search for car, and converts them to have the main object be a car
-(NSArray*)convertResultsToCars:(NSArray*)records{
NSMutableArray *manipulator =[NSMutableArray arrayWithArray:records];
NSMutableArray *convertedArray =[[NSMutableArray alloc]init];
for (int i=0; i<[manipulator count]; i++) {
CarPart *FromManipulator=(CarPart*)[manipulator objectAtIndex:i];
[convertedArray addObjectsFromArray:[[partFromManipulator toCars]allObjects]];
}
NSLog(@"Results from core data = %i",[convertedArray count]);
return [NSArray arrayWithArray:convertedArray];
}
当我从这里获取结果时，问题出现了，稍后必须在应用程序中加载所有 carParts。
Car *carResult =(Cars*)[resultsConvertedToCarsArray objectAtIndex:i];
partsFromCar =[NSMutableArray arrayWithArray:[[carResult toParts]allObjects]];
如何在我的原始查询中预取上述内容，以便此信息已加载到对象中？
这是我的原始获取请求：
NSEntityDescription *entity = [NSEntityDescription entityForName:@"CarParts" inManagedObjectContext:[self managedObjectContext]];
[fetchRequest setEntity:entity];
[fetchRequest setPredicate:[self parseCarPartsIntoAPredicate:carPartsArray]];
[fetchRequest setReturnsDistinctResults:YES];
//I guess I would use something like this? but how would I structure it?
[fetchRequest setRelationshipKeyPathsForPrefetching:@"I need to prefetch the toParts nsset of the cars found here (although in reality it brings up every instance of that car part, which I then have to convert into a car... something like found a car part, car for that part is a buick, what are the parts of the buick? ok, preload those parts"];
先感谢您！