Mongoose拯救一对多

const mongoose = require('mongoose');

// 定义用户模型
const userSchema = new mongoose.Schema({
  name: String,
  orders: [{ type: mongoose.Schema.Types.ObjectId, ref: 'Order' }]
});

const User = mongoose.model('User', userSchema);

// 定义订单模型
const orderSchema = new mongoose.Schema({
  product: String,
  price: Number,
  user: { type: mongoose.Schema.Types.ObjectId, ref: 'User' }
});

const Order = mongoose.model('Order', orderSchema);

const user = new User({ name: 'John' });
const order1 = new Order({ product: 'Product 1', price: 10, user: user._id });
const order2 = new Order({ product: 'Product 2', price: 20, user: user._id });

user.orders.push(order1._id, order2._id);

user.save();
order1.save();
order2.save();

User.findOne({ name: 'John' })
  .populate('orders')
  .exec((err, user) => {
    if (err) {
      console.error(err);
      return;
    }
    console.log(user.orders);
  });