在 mongoDB 和 node js 中添加和更新子文档（没有 mongoose）

Question

我对 node js 和 mongoDB 还很陌生，我需要在 mongodb 集合上添加或更新子文档，如下所示：

{
    "_id": "58286e49769e3729e895d239",
    "id": "2",
    "title": "Session Title",
    "sessiondate": "2016-02-11T21:00:00.000Z",
    "startTime": "14:30",
    "endTime": "16:30",
    "breakStartTime": "16:30",
    "breakEndTime": "18:00",
    "talks": [
        {
            "id": "3",
            "title": "Android",
            "speaker": {
                "id": "1",
                "name": "john doe",
                "about": "about the speaker",
                "photo": "https://pbs.twimg.com/profile_images/566353055788978177/dUy_ueY2.jpeg"
            }
        }
    ]
}

我找到的所有解决方案都是使用 mongoose，在这个特定项目中我们决定不使用 mongoose，有什么想法吗？

Answer 1

看看Node.JS MongoDB driver

基本示例

var Db = require('mongodb').Db,
    MongoClient = require('mongodb').MongoClient,
    Server = require('mongodb').Server,
    ReplSetServers = require('mongodb').ReplSetServers,
    ObjectID = require('mongodb').ObjectID,
    Binary = require('mongodb').Binary,
    GridStore = require('mongodb').GridStore,
    Grid = require('mongodb').Grid,
    Code = require('mongodb').Code,
    BSON = require('mongodb').pure().BSON,
    assert = require('assert');

  // Set up the connection to the local db
  var mongoclient = new MongoClient(new Server("localhost", 27017), {native_parser: true});

  // Open the connection to the server
  mongoclient.open(function(err, mongoclient) {

    // Get the first db and do an update document on it
    var db = mongoclient.db("integration_tests");
    db.collection('mongoclient_test').update({a:1}, {b:1}, {upsert:true}, function(err, result) {
      assert.equal(null, err);
      assert.equal(1, result);

      // Get another db and do an update document on it
      var db2 = mongoclient.db("integration_tests2");
      db2.collection('mongoclient_test').update({a:1}, {b:1}, {upsert:true}, function(err, result) {
        assert.equal(null, err);
        assert.equal(1, result);

        // Close the connection
        mongoclient.close();
      });
    });
  });

Answer 2

要在嵌入文档中添加或更新新的talk，您可以使用任何原子update operators，具体取决于集合中的文档数量 你想更新。对于单个原子更新，请使用 updateOne() 方法，如下例所示：

1.添加新的子文档

// Example of adding a subdocument to an existing document.

var MongoClient = require('mongodb').MongoClient,
    ObjectId = require('mongodb').ObjectId;

MongoClient.connect('mongodb://localhost:27017/test', function(err, db) {

    // Get a collection
    var collection = db.collection('mycollection');

    // The new talk document to be added 
    var doc = {
        "id": "4",
        "title": "PyData",
        "speaker": {
            "id": "7",
            "name": "alice bob",
            "about": "about the speaker",
            "photo": "https://pbs.twimg.com/dUy_ueY2.jpeg"
        }
    };

    // Update the document with an atomic operator
    collection.updateOne(
        { "_id": ObjectId("58286e49769e3729e895d239") },
        { "$push": { "talks": doc } },
        function(err, result){
            console.log(result);
            db.close();
        }
    )

});

在上面，您使用 $push 运算符将指定文档附加到嵌入文档数组（talks 字段）。

---

2。更新现有子文档

// Example of updating an existing subdocument.

var MongoClient = require('mongodb').MongoClient,
    ObjectId = require('mongodb').ObjectId;

MongoClient.connect('mongodb://localhost:27017/test', function(err, db) {

    // Get a collection
    var collection = db.collection('mycollection');

    // Update the document with an atomic operator
    collection.updateOne(
        { 
            "_id": ObjectId("58286e49769e3729e895d239"),
            "talk.id": "3"
        },
        { "$set": { 
            "talks.$.title": "Android version 7.0",
            "talks.$.speaker.name": "foo bar"
        } },
        function(err, result){
            console.log(result);
            db.close();
        }
    )

});

对于现有的文档更新，您可以在更新操作中应用 $set 运算符和 $ positional operator 来更改嵌入的文档字段。 $ positional operator 将识别数组中要更新的正确元素，而无需显式指定数组中元素的位置。为此，数组字段必须作为查询文档的一部分出现，因此查询

{ 
    "_id": ObjectId("58286e49769e3729e895d239"),
    "talk.id": "3" // <-- array field is part of the query
}