在mongoose中连接两个模型模式

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

const userSchema = new Schema({
  name: String,
  age: Number,
  email: String
});

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

module.exports = User;

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

const postSchema = new Schema({
  title: String,
  content: String,
  author: { type: Schema.Types.ObjectId, ref: 'User' }
});

const Post = mongoose.model('Post', postSchema);

module.exports = Post;

const mongoose = require('mongoose');
const User = require('./models/user');
const Post = require('./models/post');

mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true })
  .then(() => {
    console.log('Connected to MongoDB');
  })
  .catch((error) => {
    console.error('Error connecting to MongoDB', error);
  });

// 创建一个新的用户
const user = new User({
  name: 'John Doe',
  age: 25,
  email: 'john@example.com'
});

// 创建一个新的帖子
const post = new Post({
  title: 'Hello World',
  content: 'This is my first post',
  author: user._id
});

// 保存用户和帖子到数据库
user.save()
  .then(() => {
    return post.save();
  })
  .then(() => {
    console.log('User and post saved to database');
  })
  .catch((error) => {
    console.error('Error saving user and post to database', error);
  });