在貓鼬/節點中保存數組時如何為每個元素生成一個objectId？

Question

我正在構建一個應用程序來進行簡單的調查，我正在使用 mongoose。我設置了一個實體來定義調查，這個實體包括問題和答案

const mongoose = require("mongoose");
const {User} = require("./User");

const SurveySchema = mongoose.Schema({
    user: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'User',
        required: true
    },
    title: {
        type: String,
        minLength: 5,
        maxlength: 100,
        required: true
    },
    // other fields///
    questions: [{
        question: {
            type: String,
            minLength: 10,
            maxlength: 200,
            required: true
        },
        answers: [{
            type: String,
            minLength: 10,
            maxlength: 100,
            required: false
        }],
    }],
}, {timestamps: true} );

module.exports.Survey = mongoose.models.Survey || mongoose.model('Survey', SurveySchema);

當我需要向調查添加問題時，我正在這樣做（答案只是一個字符串數組）

let survey = await surveyManager.getSurvey(surveyId);
let newQuestion = {
  question: question,
  answers: answers
};
survey.questions.push(newQuestion);
await survey.save();
return survey;

這是我的新問題，從命令行查詢 mongodb

"questions" : [
  {
    "question" : "this is a question?",
    "answers" : [
          "answer number 1",
          "answer number 2",
          "answer number 3"
    ],
    "_id" : ObjectId("63a89d2e101149d7958e0f78")
  }
],

如您所見，每個問題都分配了一個 object id，這很好。 所以我的問題是，如何為每個答案分配一個 object id？ 我需要它來引用然后形成另一個集合。

Answer 1

我想你可以像這樣聲明你的answers ，這會自動為他們分配一個_id ：

const SurveySchema = mongoose.Schema({
 ...
 ...
    questions: [{
        question: {
            type: String,
            minLength: 10,
            maxlength: 200,
            required: true
        },
        answers: [{
            type: new mongoose.Schema({
                answer_text: {
                    type: String,
                    minLength: 10,
                    maxlength: 100,
                    required: false
                }
            })
        }]
    }],
});

Answer 2

您可以將答案設置為 object，Mongoose 將為數組中的每個項目添加一個新的_id ：

questions: [{
  question: {
    type: String,
    minLength: 10,
    maxlength: 200,
    required: true
  },
  answers: [{
    answer: {
      type: String,
      minLength: 10,
      maxlength: 100,
      required: false
    }
  }],
}],