如何从猫鼬的ID中获取名称？

Question

我有这个问题模式

const QuestionSchema = new mongoose.Schema({
    user: {
        type: Schema.Types.ObjectId,
        ref: 'users'
    },
    question:{
        type:String
    },
    name:{
        type:String,
    },
    answered:[
        {
            user:{
                type:mongoose.Schema.Types.ObjectId,
                ref:'users'
            }
        }
    ]
})

和用户模式

const UserSchema = new mongoose.Schema({
    name:{
        type:String,
        required:true
    },
    email:{
        type:String,
        required:true,
        unique:true
    },
    password:{
        type:String,
        required:true
    },
    date:{
        type:Date,
        default:Date.now
    }
})

我想获得回答用户的名字。我知道我必须使用填充，我尝试了类似const questions = await Question.find().populate('buzzed');但它不起作用。

Answer 1

您需要填写已回答的字段。

const = questions = await Question.find().populate('answered');

Answer 2

您需要这样填充：（这也是排除用户密码的好主意）

 Question.find({})
    .populate("user", "-password")
    .populate("answered.user", "-password");

还有一些代码建议：
[对于模型，我们通常使用首字母大写和单数名称，例如User。
user.js
const mongoose = require("mongoose");

const UserSchema = new mongoose.Schema({
  name: {
    type: String,
    required: true
  },
  email: {
    type: String,
    required: true,
    unique: true
  },
  password: {
    type: String,
    required: true
  },
  date: {
    type: Date,
    default: Date.now
  }
});

const User = mongoose.model("User", UserSchema);

module.exports = User;

question.js
const mongoose = require("mongoose");

const QuestionSchema = new mongoose.Schema({
  user: {
    type: mongoose.Schema.Types.ObjectId,
    ref: "User"
  },
  question: {
    type: String
  },
  name: {
    type: String
  },
  answered: [
    {
      user: {
        type: mongoose.Schema.Types.ObjectId,
        ref: "User"
      }
    }
  ]
});

const Question = mongoose.model("Question", QuestionSchema);

module.exports = Question;

并且您可以使用以下查询来填充用户：
const Question = require("../models/question");

router.get("/question", async (req, res) => {
  const questions = await Question.find({})
    .populate("user", "-password")
    .populate("answered.user", "-password");

  res.send(questions);
});

这里是示例输出：
[
    {
        "_id": "5dc12a6aa875cd0ca8b871eb",
        "user": {
            "_id": "5dc129eda875cd0ca8b871e8",
            "name": "user 1",
            "email": "[email protected]",
            "date": "2019-11-05T07:51:09.625Z",
            "__v": 0
        },
        "question": "question 1",
        "name": "question 1 name",
        "answered": [
            {
                "_id": "5dc12a6aa875cd0ca8b871ed",
                "user": {
                    "_id": "5dc12a00a875cd0ca8b871e9",
                    "name": "user 2",
                    "email": "[email protected]",
                    "date": "2019-11-05T07:51:28.892Z",
                    "__v": 0
                }
            },
            {
                "_id": "5dc12a6aa875cd0ca8b871ec",
                "user": {
                    "_id": "5dc12a0aa875cd0ca8b871ea",
                    "name": "user 3",
                    "email": "[email protected]",
                    "date": "2019-11-05T07:51:38.060Z",
                    "__v": 0
                }
            }
        ],
        "__v": 0
    }
]