通过mongo shell更新mongoDB中的嵌套数组

问题描述

以下是MongoDB文档:

Following is a MongoDB document:

{
    "_id" : 2,
    "mem_id" : M002,
    "email" : "[email protected]",
    "event_type" : [
        {
            "name" : "MT",
            "count" : 1,
            "language" : [
                {
                    "name" : "English",
                    "count" : 1,
                    "genre" : [
                        {
                            "name" : "Action",
                            "count" : 6
                        },
                        {
                            "name" : "Sci-Fi",
                            "count" : 3
                        }
                    ],
                    "cast" : [
                        {
                            "name" : "Sam Wortington",
                            "count" : 2
                        },
                        {
                            "name" : "Bruce Willis",
                            "count" : 4
                        },
                        {
                            "name" : "Will Smith",
                            "count" : 7
                        },
                        {
                            "name" : "Irfan Khan",
                            "count" : 1
                        }
                    ]
                }
            ]
        }
    ]
}

由于嵌套，我无法更新数组类型的字段，特别是event_type，语言，体裁和演员表.基本上，我想更新所有提到的四个字段以及每个和子文档的计数字段.如果值是新的，则update语句应在树中插入一个值，否则应增加该值的计数.
mongo shell中的查询可以是什么?谢谢

I'm not able to update fields that is of type array, specially event_type, language, genre and cast because of nesting. Basically, I wanted to update all the four mentioned fields along with count field for each and subdocuments. The update statement should insert a value to the tree if the value is new else should increment the count for that value.
What can be the query in mongo shell?Thanks

推荐答案

您直接遇到了MongoDB当前的限制之一.问题在于引擎不支持多个位置运算符.参见将位置$操作符多次用于更新嵌套数组

You are directly hitting one of the current limitations of MongoDB.The problem is that the engine does not support several positional operators.See this Multiple use of the positional `$` operator to update nested arrays

为此有一张公开票: https://jira.mongodb.org/browse/SERVER-831 (在此也有提及)

There is an open ticket for this: https://jira.mongodb.org/browse/SERVER-831 (mentioned also there)

您还可以阅读有关如何更改数据模型的内容:更新mongodb中的嵌套数组

You can also read this one on how to change your data model: Updating nested arrays in mongodb

如果您认为可行，则可以执行以下操作:

If it is feasible for you, you can do:

db.collection.update({_id:2,"event_type.name":'MT' ,"event_type.language.name":'English'},{$set:{"event_type.0.language.$.count":<number>}})

db.collection.update({_id:2,"event_type.name":'MT' ,"event_type.language.name":'English'},{$set:{"event_type.$.language.0.count":<number>}})

但是你不能做:

db.collection.update({_id:2,"event_type.name":'MT' ,"event_type.language.name":'English'},{$set:{"event_type.$.language.$.count":<number>}})

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