Knex Basics walkthrough

Setting up and using knex

• Must have node, the express generator, and postgres installed
• To get node and postgres:
• Install brew:

$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

• Install node and postgres

$ brew update
$ brew install node
$ brew install postgres

• Install the express generator

$ npm install express-generator -g

• Install nodemon to run your server(using the command $ nodemon) from the root directory of your application

$ npm install -g nodemon

• Note: new versions of knex have a couple of bugs, so it's advised to specifically download an older version(0.9.0) until those issues get worked out

$ take someApp
$ express --hbs --git .
$ npm install
$ npm install --save knex@0.9.0
$ npm install --save pg
$ knex init

• Open your directory in your text editor and go to your newly created knexfile.js (created by $ knex init) and replace the code there with this

module.exports = {

  development: {
    client: 'postgresql',
    connection: 'postgresql://localhost/knex-humans',
    pool: {
      min: 2,
      max: 10
    }
  }

};

• To keep it simple we'll just work with one database environment(development) and create a pointer to a knex-humans database, which we need to manually create:

$ createdb knex-humans

• Now we'll use knex to create a migrations folder and make a create_humans migrations file

$ knex migrate:make create_humans

• You should now have a migrations folder with a file in it, open it up and replace the code in there with this for the time being:

exports.up = function(knex, Promise) {
  return knex.schema.createTable('humans', function (table) {
    table.increments();
    table.string('name');
    table.integer('age');
    table.timestamps();
  })
};

exports.down = function(knex, Promise) {

};

• Now if you run this command, your schema should be correctly established in your local knex-humans postgresql database:

$ knex migrate:latest

• To properly hook knex up to your routes file you need to add this line to your routes files - in this case routes/index.js file:

var knex = require('knex')(require('../knexfile')['development']);

CRUD examples

• You can find examples of some basic CRUD in the routes/index.js file of this repository