Node.js 对象数组内的更新标志

我收到了这份文件：

{
    "_id" : ObjectId("540d881d475d68010693e340"),
    "notes" : [ 
        {
            "owner" : null,
            "creation" : 1411641315424,
            "text" : "test rec",
            "action" : "0",
            "recipients" : [ 
                {
                    "username" : "root",
                    "read" : false
                }, 
                {
                    "username" : "zivolof",
                    "read" : false
                }
            ]
        },
        {
            "owner" : null,
            "creation" : 1411641315424,
            "text" : "test rec",
            "action" : "0",
            "recipients" : [ 
                {
                    "username" : "root",
                    "read" : false
                }, 
                {
                    "username" : "zivolof",
                    "read" : false
                }
            ]
        }
    ]
}

我通过以下查询找到它：

{
    "_id": id, 
    "notes.recipients": {
         $elemMatch: {
            username: username, 
            read: false
        }
    }
}

---

然后我需要将整个文档的

read

标志更新为

true

。我该怎么办？

@FezVrasta新功能：坦斯克！所以目前还没有直接MongoDB查询的方法？