Question

我有2个表资产和奖励有关联资产＆lt; ----＆gt;奖励，当我尝试访问奖励表字段时，使用relationshipname assetrewards

NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Assets"]; 
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"assetsId == %@",str]; 
[request setPredicate:predicate]; 
[self.managedObjectContext executeFetchRequest:request onSuccess:^(NSArray *assetsArr) { 
for (Assets *assets in assetsArr) { 
NSLog(@"assets %@",[assets valueForKey:@"assetrewards.rewardsId"]); 
}
} onFailure:^(NSError *error) {

        NSLog(@"Error fetching: %@", error);

    }];

然后我收到一份崩溃报告

:  Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<Assets 0x9fb9380> valueForUndefinedKey:]: the entity Assets is not key value coding-compliant for the key "assetrewards.rewardsId".'

但是当我像智慧一样检查时

NSLog(@"assets %@",[assets valueForKey:@"assetrewards"]);

我得到这样的输出：

assets <Rewards: 0xad8a4f0> (entity: Rewards; id: 0x9fe4bf0 <x-coredata://B2D33481-2AF2-4C6D-9428-33BDCF653881-15578-00004A2B32ACC29E/Rewards/pc05848de529d4cbab6eb4475a5f9f591> ; data: <fault>)

我希望通过关系/或特定资产访问奖励字段的所有值，因为有奖励相关我想获得奖励的详细信息

Answer 1

您无法在valueForKey:等多步键路径上使用assetrewards.rewardsId。您必须使用valueForKeyPath:。如上所述，代码正在寻找一个名为assetrewards.rewardsId，而不是的密钥，该密钥名为assetrewards，该密钥通向一个名为rewardsId的密钥的对象。

访问关系对象时遇到崩溃一对一coredata / stackmob

1 个答案: