mongodb:更新嵌套字段，由两个变量提供

Question

我需要将字段content设置为id给出的point元素。

{
    "_id" : "kuwBhxAwEsJxc6oXc",
    "points" : [
        {
            "id" : "xdB8TbFweTbc9fecg",
            "pos" : [
                604,
                169
            ]
        },
        {
            "id" : "uLoorpzQWm49KZ4w3",
            "pos" : [
                197,
                176
            ]
        }
    }
}

所以我得到了docId = kuwBhxAwEsJxc6oXc，pointId = uLoorpzQWm49KZ4w3和content = 'anything'。我试过这个：

Collection.update(
    { _id: docId, 'points.id': pointId }, 
    { $set: { content: content } }
);

其结果应该是：

{
    "_id" : "kuwBhxAwEsJxc6oXc",
    "points" : [
        {
            "id" : "xdB8TbFweTbc9fecg",
            "pos" : [
                604,
                169
            ]
        },
        {
            "id" : "uLoorpzQWm49KZ4w3",
            "pos" : [
                197,
                176
            ],
            "content": "anything"
        }
    }
}

Answer 1

需要在更新中使用$运算符，如下所示：

Collection.update(
  {_id: docId, 'points.id': pointId},
  {$set: {'points.$.content': content}}
);