Now that we have created out database, in this exercise we are going to connect our application to our database using the necessary npm packages, that is, knex and mysql:

1. On the Terminal, change directory to the root of our project, and run the following command:

npm install mysql knex --save

2. Let's create a file db.js and add the following code to it, replacing the user and password appropriately if need be:

const env = process.env.NODE_ENV || 'development';
const configs = 
{
  development: 
  {
    client: 'mysql',
    ...
    const Knex = require('knex')(configs[env]);
    module.exports = Knex;

3. Let's test that we have our configurations right. We will create a test-db.js file:

const Knex = require('./db');
Knex.raw('select 1+1 as sum')
.catch((err) => console.log(err.message))
.then(([res]) => console.log('connected: ', res[0].sum));

4. Now, let's go to the Terminal and run the test file:

node test-db.js

You should get the following printed:

connected: 2