reference schema mongoose code example

Example 1: mongoose populate

Story.
  findOne({ title: /casino royale/i }).
  populate('author', 'name'). // only return the Persons name
  exec(function (err, story) {
    if (err) return handleError(err);

    console.log('The author is %s', story.author.name);
    // prints "The author is Ian Fleming"

    console.log('The authors age is %s', story.author.age);
    // prints "The authors age is null'
  });

Example 2: mongoose referenced schema

const author = new Person({
  _id: new mongoose.Types.ObjectId(),
  name: 'Ian Fleming',
  age: 50
});

author.save(function (err) {
  if (err) return handleError(err);

  const story1 = new Story({
    title: 'Casino Royale',
    author: author._id    // assign the _id from the person
  });

  story1.save(function (err) {
    if (err) return handleError(err);
    // that's it!
  });
});