时间戳

首页 > 解决方案 > MongoDB：尝试根据嵌套子文档中匹配条件的计数更新字段

mongodb - MongoDB：尝试根据嵌套子文档中匹配条件的计数更新字段

问题描述

我有下面的嵌套文档数组并尝试更新“readCounter”（这是数字）。我想将“readCounter”设置为匹配条件的文档计数：“userId”：“naveen”和“otherUserIds.otherUserId”：“ashwini”和“messages.sentBy”：“ashwini”。在以下情况下，上述条件的 readCounter 应设置为“2”。请帮助我使用 MongoDB 查询来更新“readCounter”。

我使用以下查询进行更新，但它给出了错误的结果。

AllChats.aggregate(
    [
        {
            $match: {
                userId: details.userId,
                "otherUserIds.otherUserId": details.otherUserId,
                "messages.sentBy": details.otherUserId
            }
        },
            {
                $set: { $count: "otherUserIds.$.msgReadCounter"}
            }
    ]
);

下面是数据库数据：

AllChats = [{
        "_id" : ObjectId("5f43fb76167f53d3d46b52ef"),
        "userId" : "naveen",
        "otherUserIds" : [
                {
                        "otherUserId" : "ashwini",
                        "readCounter" : 0,
                        "messages" : [
                                {
                                        "msg" : "Hi Naveen",
                                        "sentBy" : "ashwini"
                                },
                                {
                                        "msg" : "Hi Ashwini",
                                        "sentBy" : "naveen"
                                },
                                {
                                        "msg" : "How are you today",
                                        "sentBy" : "ashwini"
                                },
                                {
                                        "msg" : "I'm good",
                                        "sentBy" : "naveen"
                                }
                        ]
                },
                {
                        "otherUserId" : "testuser",
                        "readCounter" : 0,
                        "messages" : [
                                {
                                        "msg" : "Hi naveen",
                                        "sentBy" : "testuser"
                                },
                                {
                                        "msg" : "Im good",
                                        "sentBy" : "naveen"
                                },
                                {
                                        "msg" : "how are you today",
                                        "sentBy" : "testuser"
                                },
                                {
                                        "msg" : "how are you testuser",
                                        "sentBy" : "naveen"
                                }
                        ]
                }
        ]
}
{
        "_id" : ObjectId("5f440e5e167f53d3d46b52f0"),
        "userId" : "ashwini",
        "otherUserIds" : [
                {
                        "otherUserId" : "naveen",
                        "readCounter" : 0,
                        "message" : [
                                {
                                        "msg" : "Hi Naveen",
                                        "sentBy" : "ashwini"
                                },
                                {
                                        "msg" : "Hi Ashwini",
                                        "sentBy" : "naveen"
                                },
                                {
                                        "msg" : "How are you today",
                                        "sentBy" : "ashwini"
                                },
                                {
                                        "msg" : "I'm good",
                                        "sentBy" : "naveen"
                                }
                        ]
                }
        ]
}]

标签： mongodbcountmongodb-querymatchaggregate

解决方案

我自己找到了解决方案，但它很昂贵。它涉及两个独立的数据库查询，因此我愿意接受更好的解决方案。

try{
        let counter = await AllChats.aggregate([
            {$match: {userId: details.userId}},
            {$unwind: "$otherUserIds"},
            {$match: {"otherUserIds.otherUserId": details.otherUserId}},
            {$unwind: "$otherUserIds.messages"},
            {$match: {"otherUserIds.messages.sentBy": details.otherUserId}},
            {$count: "counter"}
        ]);

        console.log(counter[0]);
        if(counter[0] !== undefined){
        await AllChats.findOneAndUpdate(
            {userId: details.userId}, 
            {$set: {"otherUserIds.$[elem].msgReadCounter": counter[0].counter}},
            {arrayFilters: [{"elem.otherUserId": details.otherUserId}]}
            );
            console.log("Updated message read counter");
        }
    } catch(err){

        console.log(err);
}

推荐阅读