javascript - Mongoose 不加入两个集合

Question

所以我正在按照 mongoose 文档将两个表“连接”在一起。

http://mongoosejs.com/docs/populate.html

我有两个模式，第一个是专辑，第二个是流派。

我想从流派文档中提取所有流派，并仅填充流派名称和 albumSchema。当我点击端点查询相册时，我得到一个空对象，我按照文档中的所有内容进行操作，所以我不知道，请帮忙。

相册.js

var mongoose = require('mongoose');
var moment = require('moment');

var AlbumSchema = new mongoose.Schema({
    artist: { type: String, default: ''},
    genre: { type: String, default: ''},
    info: { type: String, default: ''},
    title: { type: String, default: ''},
    label: { type: String, default: ''},
    tracks: { type: String, default: ''},
    cover: { type: String, default: ''},
    genreDetails: [{type: mongoose.Schema.Types.ObjectId, ref: 'Genre'}],
    timestamp: {type: String, default: () => moment().format("dddd, MMMM Do YYYY, h:mm:ss a") }
});

module.exports = mongoose.model('Album', AlbumSchema);

流派.js

var mongoose = require('mongoose');
var moment = require('moment');

var GenreSchema = new mongoose.Schema({
    name: { type: String, unique: true, default: ''},
    timestamp: {type: String, default: () => moment().format("dddd, MMMM Do YYYY, h:mm:ss a") }
});

module.exports = mongoose.model('Genre', GenreSchema);

专辑 Controller .js

getAlbumDetailsAndGenres: function(id, callback) {
    Album.findById(id)
          .populate({path: 'genreDetails', select: 'name'})
          .exec(function(err, result) {
            if (err) {
                callback(err, null);
                return;
            }
            callback(null, result);
            return;
          });

}

那么我到底错过了什么？

提前致谢。

Answer 1

试试这个:

getAlbumDetailsAndGenres: function(id, callback) {
     Album.findOne({_id:new mongoose.mongo.ObjectID(id)})
          .populate('genreDetails','name')
          .exec(function(err, result) {
            if (err) {
                callback(err, null);
                return;
            }
            callback(null, result);
            return;
          });

}

保存:

genreDetails=[];

genreDetails.push(new mongoose.mongo.ObjectID('....id..here...'));


var album = new Album({
  artist:"Aerosmith",
  gerne:"Rock N Roll",
  info:"Blar",
  title:"I dont want to miss a thing",
  label:"Sony",
  tracks:10,
  cover:"Aerosmith",
  genreDetails:genreDetails
});

album.save();