Sequelize

To get our express app talking to our PostgreSQL database, we will be using Sequelize. Sequelize is an ORM (Object Relational Mapper) for SQL databases.

Sequelize takes care of communicating with our database, and converting our JavaScript data into something PostgreSQL can store.

Now it's time to get our app talking to our development database. As mentioned before, we're going to do this with Sequelize, but first we need to set a few things up:

• Install Sequelize with npm i -S sequelize

• Create a folder inside your src folder, and call it models. Add a file inside models called index.js:

  • Require sequelize at the top of this file

  • Declare a function as setupDatabase. Declare a const called connection and assign a new Sequelize() to it. Pass it the connection information from your .env

  • Still inside the function, call connection.sync({alter: true}). This gives sequelize permission to alter our tables to fit the models that we are going to create. This is useful during development because our tables are going to be changing as we add more features to the app.

  • Have the function return an empty object for now.

  • At the bottom of the file, module.exports = setupDatabase()

For now your models/index.js should look like:

const Sequelize = require('sequelize');
 
const { PGDATABASE, PGUSER, PGPASSWORD, PGHOST, PGPORT } = process.env;
 
const setupDatabase = () => {
  const connection = new Sequelize(PGDATABASE, PGUSER, PGPASSWORD, {
    host: PGHOST,
    port: PGPORT,
    dialect: 'postgres',
    logging: false,
  });
 
  connection.sync({ alter: true });
  return {};
};
 
module.exports = setupDatabase();

There is a lot going on, but for now we are just connecting to the database. We will add more to this file later as we start to define our database tables.

• Read :books: Tutorial - Sequelize with Express