无法使用Mongoose在MongoDB中保存和显示数据

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost:27017/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true })
  .then(() => {
    console.log('Connected to MongoDB');
  })
  .catch((error) => {
    console.error('Error connecting to MongoDB', error);
  });

const mongoose = require('mongoose');

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

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

const newUser = new User({ name: 'John', age: 25 });
newUser.save()
  .then(() => {
    console.log('User created successfully');
  })
  .catch((error) => {
    console.error('Error creating user', error);
  });

User.find()
  .then((users) => {
    console.log('Users:', users);
  })
  .catch((error) => {
    console.error('Error querying users', error);
  });

User.updateOne({ name: 'John' }, { age: 30 })
  .then(() => {
    console.log('User updated successfully');
  })
  .catch((error) => {
    console.error('Error updating user', error);
  });

User.deleteOne({ name: 'John' })
  .then(() => {
    console.log('User deleted successfully');
  })
  .catch((error) => {
    console.error('Error deleting user', error);
  });