Question

我正在尝试使用新的RestKit 0.9.3中的示例RKCatalog。在RKRelationshipMappingExample中，创建者忘记在Task和User之间添加连接代码，但即使在添加后也无法正常工作。

{"project": {
    "id": 123,
    "name": "Produce RestKit Sample Code",
    "description": "We need more sample code!",
    "user": {
        "id": 1,
        "name": "Blake Watters",
        "email": "blake@twotoasters.com"
    },
    "tasks": [
        {"id": 1, "name": "Identify samples to write", "assigned_user_id": 1},
        {"id": 2, "name": "Write the code", "assigned_user_id": 1},
        {"id": 3, "name": "Push to Github", "assigned_user_id": 1},
        {"id": 4, "name": "Update the mailing list", "assigned_user_id": 1}
    ]
}}

[taskMapping connectRelationship:@"assignedUser" withObjectForPrimaryKeyAttribute:@"assignedUserID"];

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        RKObjectManager* objectManager = [RKObjectManager objectManagerWithBaseURL:gRKCatalogBaseURL];
        objectManager.objectStore = [RKManagedObjectStore objectStoreWithStoreFilename:@"RKRelationshipMappingExample.sqlite"];

        RKManagedObjectMapping* taskMapping = [RKManagedObjectMapping mappingForClass:[Task class]];
        [taskMapping mapKeyPath:@"id" toAttribute:@"taskID"];
        [taskMapping setPrimaryKeyAttribute:@"taskID"];
        [taskMapping mapKeyPath:@"name" toAttribute:@"name"];
        [taskMapping mapKeyPath:@"assigned_user_id" toAttribute:@"assignedUserID"];
        [taskMapping connectRelationship:@"assignedUser" withObjectForPrimaryKeyAttribute:@"assignedUserID"];
        [objectManager.mappingProvider setMapping:taskMapping forKeyPath:@"task"];

        RKManagedObjectMapping* userMapping = [RKManagedObjectMapping mappingForClass:[User class]];
        [userMapping mapAttributes:@"name", @"email", nil];
        [userMapping mapKeyPath:@"id" toAttribute:@"userID"];
        [userMapping setPrimaryKeyAttribute:@"userID"];
        [userMapping mapRelationship:@"tasks" withMapping:taskMapping];
        [objectManager.mappingProvider setMapping:userMapping forKeyPath:@"user"];

        // NOTE - Project is not backed by Core Data
        RKObjectMapping* projectMapping = [RKObjectMapping mappingForClass:[Project class]];
        [projectMapping mapKeyPath:@"id" toAttribute:@"projectID"];
        [projectMapping mapAttributes:@"name", @"description", nil];
        [projectMapping mapRelationship:@"user" withMapping:userMapping];
        [projectMapping mapRelationship:@"tasks" withMapping:taskMapping];
        [objectManager.mappingProvider setMapping:projectMapping forKeyPath:@"project"];
    }

    return self;
}

我做的一切都好吗？ - 它不会按用户的ID将任务连接到用户。

Answer 1

更新：我应该更仔细地阅读Blake's linked post - 它会更快地将我指向开发部门。

BOTTOM LINE：一对多映射问题（在User对象的tasks的反向水合作用的上下文中讨论）在0.9中已破坏。 3。截至2012年3月8日，开发部门的拉动证实了问题在那里得到了解决--Blake在问题＃284中解决了这个问题。您执行仍需要添加示例中不包含的connectRelationship:withObjectForPrimaryKeyAttribute:逻辑。

@Evan，感谢RKLogConfigureByName("RestKit/ObjectMapping", RKLogLevelTrace)上的提示 - 这对于分析实际发生的事情很有帮助。

我仍然非常喜欢RestKit的“找到我的方式”阶段，所以YMMV。但是，根据this post by Blake，它实际上看起来你需要两者 - 这是我能让这个例子工作的唯一方法。但是，对相关对象的主键的引用是使用它的本地[即Task的ivar]属性引用的：

        RKManagedObjectMapping* taskMapping = [RKManagedObjectMapping mappingForClass:[Task class]];
        [taskMapping mapKeyPath:@"id" toAttribute:@"taskID"];
        [taskMapping mapKeyPath:@"name" toAttribute:@"name"];
        [taskMapping mapKeyPath:@"assigned_user_id" toAttribute:@"assignedUserID"];
        taskMapping.primaryKeyAttribute = @"taskID";

        RKManagedObjectMapping* userMapping = [RKManagedObjectMapping mappingForClass:[User class]];
        [userMapping mapAttributes:@"name", @"email", nil];
        [userMapping mapKeyPath:@"id" toAttribute:@"userID"];
        [userMapping mapRelationship:@"tasks" withMapping:taskMapping];
        userMapping.primaryKeyAttribute = @"userID";
        [objectManager.mappingProvider setMapping:userMapping forKeyPath:@"user"];

        [taskMapping mapRelationship:@"assignedUser" withMapping:userMapping];
        [taskMapping connectRelationship:@"assignedUser" withObjectForPrimaryKeyAttribute:@"assignedUserID"];
        [objectManager.mappingProvider setMapping:taskMapping forKeyPath:@"task"];

这是针对大约3天前的大师拉动的。

Answer 2

用户 - ＆gt;任务映射是在userMapping上设置的，行[userMapping mapRelationship:@"tasks" withMapping:taskMapping];。我假设你说的是没有创建反转？

如果这是问题，我想你会发现this commit解决了这个问题，尽管我还没有尝试过。（您可以在该点拉树，或者更好地拉动当前的主分支）。

除此之外，您对行[taskMapping connectRelationship:@"assignedUser" withObjectForPrimaryKeyAttribute:@"assignedUserID"];有疑问。它正在搜索主键属性为“assignedUserID”的对象，但查看其他映射时，不存在此类对象。请注意，在userMapping上，主键由[userMapping setPrimaryKeyAttribute:@"userID"];

定义

您可能想要[taskMapping connectRelationship:@"assignedUser" withObjectForPrimaryKeyAttribute:@"userID"];，甚至更好[taskMapping mapRelationship:@"assignedUser" withMapping:userMapping];

（通过我链接的提交，我甚至不确定是否有必要添加任何内容以获得反向 - 您可以尝试两者并查看。）

如果仍有问题，您可以使用RKLogConfigureByName("RestKit/ObjectMapping", RKLogLevelTrace);

打开ObjectMapper的日志

Answer 3

我一直在搞这个代码差不多一个半小时，最后还是开始工作了。我采取的步骤： 1）重新排列如下关系的创建 2）取消选中RKRelationshipMappingExample.xcdatamodel＆gt;的“可选”复选标记。 task.assignedUser relationship。我注意到它既是“可选的”，也是最小值1，最大值1.我在此更改后删除了应用程序并重新安装了它。现在，用户被添加到用户的任务和任务中！

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        RKObjectManager* objectManager = [RKObjectManager objectManagerWithBaseURL:gRKCatalogBaseURL];
        objectManager.objectStore = [RKManagedObjectStore objectStoreWithStoreFilename:@"RKRelationshipMappingExample.sqlite"];


        RKManagedObjectMapping* taskMapping = [RKManagedObjectMapping mappingForClass:[Task class]];
        [taskMapping mapKeyPath:@"id" toAttribute:@"taskID"];
        [taskMapping mapKeyPath:@"name" toAttribute:@"name"];
        [taskMapping mapKeyPath:@"assigned_user_id" toAttribute:@"assignedUserID"];
        taskMapping.primaryKeyAttribute = @"taskID";

        RKManagedObjectMapping* userMapping = [RKManagedObjectMapping mappingForClass:[User class]];
        [userMapping mapAttributes:@"name", @"email", nil];
        [userMapping mapKeyPath:@"id" toAttribute:@"userID"];

        userMapping.primaryKeyAttribute = @"userID";
        [objectManager.mappingProvider setMapping:userMapping forKeyPath:@"user"];
        [objectManager.mappingProvider setMapping:taskMapping forKeyPath:@"task"];

        [userMapping mapRelationship:@"tasks" withMapping:taskMapping];        
        [taskMapping mapRelationship:@"assignedUser" withMapping:userMapping];

        [taskMapping connectRelationship:@"assignedUser" withObjectForPrimaryKeyAttribute:@"assignedUserID"];


        // NOTE - Project is not backed by Core Data
        RKObjectMapping* projectMapping = [RKObjectMapping mappingForClass:[Project class]];
        [projectMapping mapKeyPath:@"id" toAttribute:@"projectID"];
        [projectMapping mapAttributes:@"name", @"description", nil];
        [projectMapping mapRelationship:@"user" withMapping:userMapping];
        [projectMapping mapRelationship:@"tasks" withMapping:taskMapping];
        [objectManager.mappingProvider setMapping:projectMapping forKeyPath:@"project"];



    }

    return self;
}

//to see NSLog messages, change the LOGGER_DEBUG to 2 (in LoggerClient.m) like this:
#define LOGGER_DEBUG 2
#ifdef NSLog
    #undef NSLog
#endif



//test method to make sure all relationships are created.
- (void)objectLoader:(RKObjectLoader *)objectLoader didLoadObjects:(NSArray *)objects {
    _objects = [objects retain];

    for(Project* managedObject in objects)
    {   NSLog(@" project user: %@", [managedObject.user description]);
        NSLog(@"###### user tasks count: %i",[managedObject.user.tasks  count]);
        for(Task* task in managedObject.user.tasks)
        {
            NSLog(@"+++++managedObject.user.tasks: %@", [task description]);
        }

        for(Task* task in managedObject.tasks)
        {
            NSLog(@"*****task: %@", [task description]);
        }

    }
    [self.tableView reloadData];
}

RestKit 0.9.3 connectRelationship：withObjectForPrimaryKeyAttribute：

3 个答案: