猫鼬填充返回空数组 [英] mongoose populate returns null array

问题描述

猫鼬在人口中的表现并不理想.这是我的模特

Mongoose isnt playing very well with population. this is my model

var mongoose = require('mongoose'),
Schema = mongoose.Schema;

mongoose.connect(process.env.MONGO_URI);

var userSchema = new Schema({
  username: String,
  password: String,
  books: [{type: Schema.Types.ObjectId, ref: 'User'}]
  }
);

var bookSchema = new Schema({
  bookid: {type:String, unique:true, required:true},
  imgURL: String
});

module.exports.user = mongoose.model('User', userSchema);
module.exports.book = mongoose.model('Book', bookSchema);

数据库看起来正确.

{ "_id" : ObjectId("56a17cd70a498fcc37cdbe60"), "username" : "test", "password" : "test", "books" : [ ObjectId("56a17d21d43dc32a3a9837de"), ObjectId("56a17ee5d43dc32a3a9837e4"), ObjectId("56a17f5dd43dc32a3a9837e6"), ObjectId("56a17f9fd43dc32a3a9837e8") ], "__v" : 4 }

但是当我进行填充时，会得到一个空的'books'数组

But when I do a populate I get an empty 'books' array

users.findOne({'_id':userid}).populate('books').exec(function(err,data){
            if (err) return console.error(err);

            if(data){

            }
});

所有内容都不会被填充.任何建议将不胜感激.

Everything is there it simply will not populate. Any suggestions would be greatly appreciated.

推荐答案

userSchema中的ref似乎不正确，它应该引用book模式而不是user模式本身.

It seems the incorrect ref in the userSchema, it should reference to book schema rather than user schema itself.

var book = mongoose.model('Book', bookSchema);

...
books: [{type: Schema.Types.ObjectId, ref: 'book'}]

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