loopback-datasource-juggler/examples/relations.js

var DataSource = require('../index').DataSource;
var ds = new DataSource('memory');

var Order = ds.createModel('Order', {
  customerId: Number,
  orderDate: Date
});

var Customer = ds.createModel('Customer', {
  name: String
});

Order.belongsTo(Customer);

Customer.create({name: 'John'}, function (err, customer) {
  Order.create({customerId: customer.id, orderDate: new Date()}, function (err, order) {
    order.customer(console.log);
    order.customer(true, console.log);

    Customer.create({name: 'Mary'}, function (err, customer2) {
      order.customer(customer2);
      order.customer(console.log);
    });
  });
});

Customer.hasMany(Order, {as: 'orders', foreignKey: 'customerId'});

Customer.create({name: 'Ray'}, function (err, customer) {
  Order.create({customerId: customer.id, orderDate: new Date()}, function (err, order) {
    customer.orders(console.log);
    customer.orders.create({orderDate: new Date()}, function (err, order) {
      console.log(order);
      Customer.include([customer], 'orders', function (err, results) {
        console.log('Results: ', results);
      });
      customer.orders.findById('2', console.log);
      customer.orders.destroy('2', console.log);
    });
  });
});

var Physician = ds.createModel('Physician', {
  name: String
});

var Patient = ds.createModel('Patient', {
  name: String
});

var Appointment = ds.createModel('Appointment', {
  physicianId: Number,
  patientId: Number,
  appointmentDate: Date
});

Appointment.belongsTo(Patient);
Appointment.belongsTo(Physician);

Physician.hasMany(Patient, {through: Appointment});
Patient.hasMany(Physician, {through: Appointment});

Physician.create({name: 'Smith'}, function (err, physician) {
  Patient.create({name: 'Mary'}, function (err, patient) {
    Appointment.create({appointmentDate: new Date(), physicianId: physician.id, patientId: patient.id},
      function (err, appt) {
        physician.patients(console.log);
        patient.physicians(console.log);
      });
  });
});

var Assembly = ds.createModel('Assembly', {
  name: String
});

var Part = ds.createModel('Part', {
  partNumber: String
});

Assembly.hasAndBelongsToMany(Part);
Part.hasAndBelongsToMany(Assembly);

Assembly.create({name: 'car'}, function (err, assembly) {
  Part.create({partNumber: 'engine'}, function (err, part) {
    assembly.parts.add(part, function (err) {
      assembly.parts(console.log);
    });

  });
});