Mongoose：无法使用$ addToSet或$ push将新对象添加/推送到数组

2 回答

• 1

  我会打电话给"bug" . Mongoose显然做了错误的事情，如后面所示的日志记录中可以证明的那样 . 但是这里有一个列表，它使用您尝试执行的相同更新从本机驱动程序调用 .findOneAndUpdate() ：

  var async = require('async'),
      mongoose = require('mongoose'),
      Schema = mongoose.Schema;
  
  mongoose.connect('mongodb://localhost/school');
  mongoose.set('debug',true);
  
  var userSchema = new Schema({
    name: {
      type: String,
      required: true
    },
    lectures: { type: Schema.Types.Mixed }
  });
  
  var User = mongoose.model( "User", userSchema );
  
  function logger(data) {
    return JSON.stringify(data, undefined, 2);
  }
  
  async.waterfall(
    [
      function(callback) {
        User.remove({},function(err) {
          callback(err);
        });
      },
      function(callback) {
        console.log("here");
        var user = new User({ "name": "bob" });
        user.save(function(err,user) {
          callback(err,user);
        });
      },
      function(user,callback) {
        console.log("Saved: %s", logger(user));
        User.collection.findOneAndUpdate(
          { "_id": user._id },
          {
            "$addToSet": {
              "lectures.physics.topic": {
                "name": "Fluid Mechanics",
                "day": "Monday",
                "faculty": "Nancy Wagner"
              }
            }
          },
          { "returnOriginal": false },
          function(err,user) {
            callback(err,user);
          }
        );
      }
    ],
    function(err,user) {
      if (err) throw err;
      console.log("Modified: %s", logger(user));
      mongoose.disconnect();
    }
  );
  

  这与结果完美配合：

  Saved: {
    "__v": 0,
    "name": "bob",
    "_id": "55cda1f5b5ee8b870e2f53bd"
  }
  Modified: {
    "lastErrorObject": {
      "updatedExisting": true,
      "n": 1
    },
    "value": {
      "_id": "55cda1f5b5ee8b870e2f53bd",
      "name": "bob",
      "__v": 0,
      "lectures": {
        "physics": {
          "topic": [
            {
              "name": "Fluid Mechanics",
              "day": "Monday",
              "faculty": "Nancy Wagner"
            }
          ]
        }
      }
    },
    "ok": 1
  }
  

  你需要小心，因为本机驱动程序方法不像mongoose方法那样知道连接状态 . 因此，您需要确保通过先前触发的“mongoose”方法 Build 连接，或者将您的应用程序包装在连接事件中，如下所示：

  mongoose.connection.on("connect",function(err) {
     // start app in here
  });
  

  ---

  至于“bug”，请查看此列表的日志记录输出：

  var async = require('async'),
      mongoose = require('mongoose'),
      Schema = mongoose.Schema;
  
  mongoose.connect('mongodb://localhost/school');
  mongoose.set('debug',true);
  
  var userSchema = new Schema({
    name: {
      type: String,
      required: true
    },
    lectures: { type: Schema.Types.Mixed }
  });
  
  var User = mongoose.model( "User", userSchema );
  
  function logger(data) {
    return JSON.stringify(data, undefined, 2);
  }
  
  async.waterfall(
    [
      function(callback) {
        User.remove({},function(err) {
          callback(err);
        });
      },
      function(callback) {
        console.log("here");
        var user = new User({ "name": "bob" });
        user.save(function(err,user) {
          callback(err,user);
        });
      },
      function(user,callback) {
        console.log("Saved: %s", logger(user));
        User.findByIdAndUpdate(
          user._id,
          {
            "$addToSet": {
              "lectures.physics.topic": {
                "name": "Fluid Mechanics",
                "day": "Monday",
                "faculty": "Nancy Wagner"
              }
            }
          },
          { "new": true },
          function(err,user) {
            callback(err,user);
          }
        );
      }
    ],
    function(err,user) {
      if (err) throw err;
      console.log("Modified: %s", logger(user));
      mongoose.disconnect();
    }
  );
  

  并且使用mongoose日志记录的记录输出：

  Mongoose: users.remove({}) {}
  here
  Mongoose: users.insert({ name: 'bob', _id: ObjectId("55cda2d2462283c90ea3f1ad"), __v: 0 })
  Saved: {
    "__v": 0,
    "name": "bob",
    "_id": "55cda2d2462283c90ea3f1ad"
  }
  Mongoose: users.findOne({ _id: ObjectId("55cda2d2462283c90ea3f1ad") }) { new: true, fields: undefined }
  Modified: {
    "_id": "55cda2d2462283c90ea3f1ad",
    "name": "bob",
    "__v": 0
  }
  

  所以在真正的"What the Fudge?"风格中，有一个叫 .findOne() 的电话？这不是问的问题 . 此外，当然数据库中没有任何改变，因为进行了错误的调用 . 所以即使这里的 { "new": true } 也是多余的 .

  这种情况发生在具有“混合”模式类型的所有级别 .

  就个人而言，我不会像这样嵌套在“对象”中，只需将“对象键”作为标准数组的一部分作为附加属性 . MongoDB和mongoose都对此更加满意，并且查询具有这种结构的信息要容易得多 .

  var async = require('async'),
      mongoose = require('mongoose'),
      Schema = mongoose.Schema;
  
  mongoose.connect('mongodb://localhost/school');
  mongoose.set('debug',true);
  
  var lectureSchema = new Schema({
    "subject": String,
    "topic": String,
    "day": String,
    "faculty": String
  });
  
  var userSchema = new Schema({
    name: {
      type: String,
      required: true
    },
    lectures: [lectureSchema]
  });
  
  var User = mongoose.model( "User", userSchema );
  
  function logger(data) {
    return JSON.stringify(data, undefined, 2);
  }
  
  async.waterfall(
    [
      function(callback) {
        User.remove({},function(err) {
          callback(err);
        });
      },
      function(callback) {
        console.log("here");
        var user = new User({ "name": "bob" });
        user.save(function(err,user) {
          callback(err,user);
        });
      },
      function(user,callback) {
        console.log("Saved: %s", logger(user));
        User.findByIdAndUpdate(
          user._id,
          {
            "$addToSet": {
              "lectures": {
                "subject": "physics",
                "topic": "Fluid Mechanics",
                "day": "Monday",
                "faculty": "Nancy Wagner"
              }
            }
          },
          { "new": true },
          function(err,user) {
            callback(err,user);
          }
        );
      }
    ],
    function(err,user) {
      if (err) throw err;
      console.log("Modified: %s", logger(user));
      mongoose.disconnect();
    }
  );
  

  输出：

  Mongoose: users.remove({}) {}
  here
  Mongoose: users.insert({ name: 'bob', _id: ObjectId("55cda4dc40f2a8fb0e5cdf8b"), lectures: [], __v: 0 })
  Saved: {
    "__v": 0,
    "name": "bob",
    "_id": "55cda4dc40f2a8fb0e5cdf8b",
    "lectures": []
  }
  Mongoose: users.findAndModify({ _id: ObjectId("55cda4dc40f2a8fb0e5cdf8b") }) [] { '$addToSet': { lectures: { faculty: 'Nancy Wagner', day: 'Monday', topic: 'Fluid Mechanics', subject: 'physics', _id: ObjectId("55cda4dc40f2a8fb0e5cdf8c") } } } { new: true, upsert: false, remove: false }
  Modified: {
    "_id": "55cda4dc40f2a8fb0e5cdf8b",
    "name": "bob",
    "__v": 0,
    "lectures": [
      {
        "faculty": "Nancy Wagner",
        "day": "Monday",
        "topic": "Fluid Mechanics",
        "subject": "physics",
        "_id": "55cda4dc40f2a8fb0e5cdf8c"
      }
    ]
  }
  

  这样工作正常，你不需要挖掘原生方法只是为了让它工作 .

  数组的属性使查询和过滤非常容易，以及跨数据的“聚合”信息，对于所有这些信息，MongoDB都喜欢引用所有信息的“严格路径” . 否则，您只是“特定键”，并且在不提及每个可能的“键组合”的情况下，无法对其进行索引或搜索 .

  像这样的属性是一个更好的方法 . 这里没有错误 .

  回复于 2024-05-01T11:57:39+08:00
• 2

  Mongoose失去了自动检测并保存对Mixed类型所做更改的功能，因此您需要通过调用文档的 .markModified(path) 方法来更改混合类型的值，该方法将路径传递给您刚刚更改的Mixed类型：

  doc.mixed.type = 'changed';
  doc.markModified('mixed.type');
  doc.save() // changes to mixed.type are now persisted
  

  在您的情况下，您可以使用 findById() 方法通过调用主题数组上的 addToSet() 方法进行更改，然后触发 save() 方法来保留更改：

  userModel.findById(user._id, function (err, doc){
      var item = {
          "name": "Fluid Mechanics",
          "day": "Monday",
          "faculty": "Nancy Wagner"
      };
      doc.lectures.physics.topic.addToSet(item);
      doc.markModified('lectures');
      doc.save() // changes to lectures are now persisted 
  });
  

  回复于 2024-05-01T11:57:39+08:00