在尝试连接两个文档时，无法在Mongoose中填充路径

Question

Mongoose错误：无法填充路径loaned_to，因为它不在您的模式中。将strictPopulate选项设置为false以进行覆盖。

我尝试使用Node.js中的Mongoose连接两个MongoDB文档，但不幸的是出现了这个错误。我的Mongoose版本是6.0.6

图书模式

const mongoose = require('mongoose');

const BookSchema = new mongoose.Schema({
    "name": {type: String, required: true},
    "author_name": {type: String, required: true},
    "published_date": {type: Date, required: false},
    "copies": [
        {
            "isbn_number": {type: String, required: true},
            "status": {type: String, required: true, default: "Available"},
            "due_back": {type: Date, required: false},
            "loaned_to": {type: mongoose.Schema.Types.ObjectId, required: false, ref: "User"}
        },
    ]
})

const Book = mongoose.model("Book", BookSchema);
module.exports = Book;

用户模式

const mongoose = require('mongoose');

const UserSchema = new mongoose.Schema({
    "first_name": {type: String, required: true},
    "last_name": {type: String, required: true},
    "phone_number": {type:  String, required: true},
    "address": {type:  String, required: false},
    "user_name":{type: String, required: true},
    "password": {type:  String, required: true},
    "email": {type:  String, required: true},
    "notifications": [
        {
            "notification_id" : {type:"string", required:true},
            "notification": {type: "string", required: true}
        },
    ]
})

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

我的代码连接文档

exports.getAllBooks = async (req, res) => {
    try {
        let data = await BookModel.findOne().populate("loaned_to");
        res.status(200).send({data: [...data], success: true})
    } catch (err) {
        console.log(err)
        res.status(404).send({success: false, msg: err.message})
    }
}

- Rishi

---

路径: 'copies.loaned_to' <==== 任何人遇到这个问题。 这是由于在填充或字段名称中传递了模式名称导致的。 - Shah Vipul

Answer 1

exports.getAllBooks = async (req, res) => {
  try {
    let data = await BookModel.findOne().populate({
      path: 'copies.loaned_to',
      select:
        'first_name lastName phone_number address user_name email notifications',
    });
    res.status(200).json({ data: [...data], success: true });
  } catch (err) {
    console.log(err);
    res.status(500).json({ success: false, msg: err.message });
  }
};

- user2601376

Answer 2

使用嵌套populate，就像下面的例子一样（该示例假设Token模型有一个用户，用户又有一个角色，并且角色有权限）。这将返回与过滤令牌相关联的用户对象，具有分配给用户的角色以及分配给角色的权限。

即：TokenModel（与之相关联） -> UserModel（与之相关联） -> RoleModel（与之相关联） -> PermissionsModel）

const popObj = {
        path: 'user',
        options: { sort: { position: -1 } },
        populate: {
          path: 'role',
          select: 'name',
          populate: {
            path: 'permissions'
          }
        }
};
const tokenFilter = {is_active: true};
TokenModel.find(userFilter).populate(popObj);

- Elijah Baraza