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Am newbie to RDBMS and Sequelize as well wanted to explore more in those now am struck up with JOINS. I don't know how to perform JOINS via SEQUELIZE. I have 3 tables USERS,ORDERS,PRODUCTS ORDERS table contains USERS,PRODUCTS primary key as its foreign key. Am attaching my model code below User Model

const Sequelize = require('sequelize');
const sequelize = require('../config');
let Users = sequelize.define('users', {
  id : {
    type: Sequelize.INTEGER,
    primaryKey: true,
    autoIncrement: true
  },
  username: {
    type: Sequelize.STRING,
  },
  password: {
    type: Sequelize.STRING
  }
});
module.exports = Users;

Products Model

const Sequelize = require('sequelize');
const sequelize = require('../config');
let products=sequelize.define('products', {
  id : {
    type: Sequelize.INTEGER,
    primaryKey: true,
    autoIncrement: true
  },
  category : {
    type: Sequelize.STRING,
    allowNull: false
  },
  name : {
    type: Sequelize.STRING,
    allowNull: false
  },
  price: {
    type: Sequelize.INTEGER,
    allowNull: false
  }
});
module.exports= products;

Orders Model

const Sequelize = require('sequelize');
const sequelize = require('../config');
let users=require('./user');
let products=require('./product');
let orders=sequelize.define('orders', {
  id: {
    type: Sequelize.INTEGER,
    primaryKey: true,
    autoIncrement: true
  },
  user_id: {
    type: Sequelize.INTEGER,
    references: {
        model: 'users',
        key: 'id'
    }
  },
  product_id: {
    type: Sequelize.INTEGER,
    references: {
        model: 'products',
        key: 'id'
    }
  },
  price: {
    type: Sequelize.INTEGER,
    allowNull: false
  }
});
module.exports= orders;

I want this following raw query to be performed via SEQUELIZE

SELECT * FROM ((orders INNER JOIN users ON users.id=orders.user_id) INNER JOIN products ON products.id=orders.product_id);

I have looked at the documentation but i couldn't figure out how to do it. ANy help is appreciated. Thanks

Answers

First thing you need to do is set up your Associations.

So lets break this up in to parts. We know that your ORDERS table contains the id for a USER and a PRODUCT. So this is how you would set up your associations for these tables.

1. I am assuming that a user has many orders. We make the associations in both directions.

   User.hasMany(Orders, {foreignKey: 'user_id'}); Order.belongsTo(User, {foreignKey: 'user_id'});

You have the model correctly defined it seems.

2. Now in order to do a join, after setting up the associations, we want to set up a query to do joins for tables. Now keep in mind this would be done in your controller.

// Make sure you import your models up here to use below

export function getRequestsByWeek(req, res) {
  return order.findAll({
    include: [
      {model: users, attributes: []}, // nothing in attributes here in order to not import columns from users
      {model: products} // nothing in attributes here in order to not import columns from products
    ],
    attributes: ['id'], //in quotes specify what columns you want, otherwise you will pull them all
    // Otherwise remove attributes above this line to import everything. 
  })
    .then(respondWithResult(res))
    .catch(handleError(res));
}