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另一天。另一个 Mongodb 查询。

我希望在我的一个集合中创建以下结构：

amitverma是用户，嵌套对象是消息的 UTC 时间戳。我想按以下结构推送消息。

{
    "username" : "macbook",
    "messages" : {
        "amitverma" : {
            "1383321755" : {
                "to" : "macbook",
                "message" : "hi.",
                "sender" : "amitverma",
            },
            "1383321712" : {
                "to" : "macbook",
                "message" : "hi.",
                "sender" : "amitverma",
            }
        }
    },
    "_id" : ObjectId("5273d09ab743db7a5f000001")
}

我不能使用 $push 或 $addToSet 因为它不是一个数组。或者我可以吗？

另外，我现在有以下代码：

var pushNotification = {};
    var addon = {};
    var anotheraddon = {};
    var utcTime = arrayOps.encodeTime();

    addon[data.sender] = [];
    anotheraddon[utcTime] = data;
    addon[data.sender].push(anotheraddon);

    // var a = pushNotification;
    // a.push(anotheraddon);
    // console.log(pushNotification);

    pushNotification['messages'] = {}
    pushNotification['messages'][data.sender] = [];
    pushNotification['messages'][data.sender] = data;

    var a = 'messages.' + data.sender + '.$';


    console.log('push object');
    console.log(pushNotification);
    co_notifications.update(
        {'username': data.to}, 
        { $addToSet: pushNotification}, function(err, docs){
            console.log(err);
            console.log(docs);
            if (docs == 0){
                co_notifications.insert(
                    {'username': data.to, 'messages': addon}, function(er, doc){
                });
            }
        },
        {upsert: true}
    );

原谅垃圾代码。上面的代码导致了这个结构：

{
    "username" : "macbook",
    "messages" : {
        "amitverma" : [
            {
                "1383321755" : {
                    "to" : "macbook",
                    "message" : "hi.",
                    "sender" : "amitverma",
                }
            }
        ]
    },
    "_id" : ObjectId("5273d09ab743db7a5f000001")
}

这不是我想要的。

有没有一种方法可以创建我想要的结构并轻松读取和更新？谢谢。

4

1 回答 1

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You can insert additional elements of the form you outlined above to an existing document by using the following update:

info = {"to": "...", "message": "...",  "sender": "..."}
c.update({}, {$set: {'messages.amitverma.1111111111': info}})

After executing this update on your example document the result is:

{
    "_id" : ObjectId("5273d09ab743db7a5f000001"),
    "messages" : {
        "amitverma" : {
            "1111111111" : {
                "to" : "...",
                "message" : "...",
                "sender" : "..."
            },
            "1383321712" : {
                "to" : "macbook",
                "message" : "hi.",
                "sender" : "amitverma"
            },
            "1383321755" : {
                "to" : "macbook",
                "message" : "hi.",
                "sender" : "amitverma"
            }
        }
    },
    "username" : "macbook"
}

You don't say what kind of queries you want to do, but here's an example that shows the kind of thing you might do. This query finds a document with a give username, and uses a projection to return only a specific subset of the document, in this example the element that we just added:

c.findOne({username:'macbook'}, {'messages.amitverma.1111111111':1})

This query produces the following result:

{
    "_id" : ObjectId("5273d09ab743db7a5f000001"),
    "messages" : {
        "amitverma" : {
            "1111111111" : {
                "to" : "...",
                "message" : "...",
                "sender" : "..."
            }
        }
    }
}

Hope this helps,

Bruce

于 2013-11-01T17:00:47.107 回答