引用文档属性以在 mongo 更新查询中更新另一个 [英] Referencing the document attribute to update another in mongo update query

问题描述

{
    "_id" : ObjectId("57693a852956d5301b348a99"),
    "First_Name" : "Sri Ram",
    "Last_Name" : "Bandi",
    "Email" : "[e-mail]",
    "Sessions" : [
        {
            "Class" : "facebook",
            "ID" : "1778142655749042",
            "Login_Time" : ISODate("2016-06-21T13:00:53.867Z"),
            "Logout_Time" : ISODate("2016-06-21T13:01:04.640Z"),
            "Duration" : null
        }
    ],
    "Count" : 1
}

这是我的mongo数据，我想将注销时间设置为当前时间，将持续时间"设置为同时登录和注销时间的差值.所以我执行了以下查询:

This is my mongo data and I want to set the logout time as current time and "duration" as the difference of login and logout time simultaneously. So I executed the following query:

collection.update(
    {
        "Sessions.ID": 1778142655749042, 
        "Sessions.Logout_Time": null
    },
    {  
        "$set": {
            "Sessions.$.Logout_Time": new Date(),
            "Sessions.$.Duration": new Date(new Date() - "$Sessions.$.Login_Time"),
        }, 
    }
);

但我得到的结果是将注销时间设置为当前时间，但持续时间设置为NaN".

But the result I'm getting is setting logout time as current time but duration is set to 'NaN'.

推荐答案

Mongo 不支持在更新中引用当前对象

所以你可以做的是:

  db.collection.find( { "Sessions.ID": 1778142655749042, "Sessions.Logout_Time": null
    }).forEach(function(doc){

       for(var session in doc.Sessions){
           if(!session.Logout_Time){
               session.Logout_Time =  new Date();
               session.Duration = new Date(new Date() - doc.Login_Time");
             }

       }

db.collection.save(doc);

});

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