猫鼬子文档 field.id 给出未定义

Question

在此代码中，我需要使用其生成的 id 获取 batch_results，如中所述 猫鼬文档

const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const config = require('../config/config');



// Result schema
const ResultsSchema = new Schema({
    subject_id: {
        type: mongoose.SchemaTypes.ObjectId,
        required: false
    },
    marks: {
        type: [String], // when needed to store absent as well
        required: false
    }
});

// Batch Schema
const BatchSchema = new Schema({
    student_base_no: {
        type: mongoose.SchemaTypes.ObjectId,
        required: false,
    },
    results: [ResultsSchema]
});

// Marks schema
const MarksSchema = new Schema({

    date: {
        type: Date,
        default: Date.now,
        required: true
    },
    year: {
        type: String,
        default: (new Date).getFullYear(),
        required: true
    },
    batch: {
        type: String,
        required: true
    },
    batch_results: [BatchSchema]

});



const Marks = module.exports = mongoose.model('marks', MarksSchema, 'marks');

使用此代码我尝试获取输出，

var a = Marks.batch_results.id(id)

但它一直说 Cannot read property 'id' of undefined

我尝试了很多，但效果不佳:( 请帮帮我...

Answer 1

您需要更改批次和标记架构：

const BatchSchema = new Schema({
    student_base_no: {
        type: mongoose.SchemaTypes.ObjectId,
        required: false,
    },
    results:{
         type: Schema.Types.ObjectId,
          ref: 'results' 
       }
})