Cheat Sheet: Setting up Express with Postgres via Knex

express_postgress_knex.md

Express & Postgres via Knex

Note: <example> is meant to denote text replaced by you (including brackets).

Setup

// global dependencies
npm install -g knex

// project's dependencies
npm install knex pg --save

// project's dev dependencies
npm nodemon --save-dev

DB Setup

$ psql

CREATE DATABASE <example>;
CREATE DATABASE <example_test>;

Knex

Config

$ knex init
Created ./knexfile.js

Replace contents of ./knexfile.js with:

module.exports = {
  development: {
    client: 'pg',
    connection:'postgres://localhost/<examples>',
    migrations: {
      directory: './db/migrations'
    },
    seeds: {
      directory: './db/seeds/dev'
    },
    useNullAsDefault: true
  },

  test: {
    client: 'pg',
    connection:'postgres://localhost/<examples_test>',
    migrations: {
      directory: './db/migrations'
    },
    seeds: {
      directory: './db/seeds/test'
    },
    useNullAsDefault: true
  },

  production: {
    client: 'pg',
    connection: process.env.DATABASE_URL,
    migrations: {
      directory: './db/migrations'
    },
    seeds: {
      directory: './db/seeds/production'
    },
    useNullAsDefault: true
  }
}

Migrations

Create Table

$ knex migrate:make create-<example>-table

up and down Functions

Populate those functions in your migrations/<example>.js file. For example:

exports.up = function(knex, Promise) {
  let createQuery = `CREATE TABLE <examples>(
    id SERIAL PRIMARY KEY NOT NULL,
    message TEXT,
    created_at TIMESTAMP
  )`
  return knex.raw(createQuery)
}

exports.down = function(knex, Promise) {
  let dropQuery = `DROP TABLE <examples>`
  return knex.raw(dropQuery)
}

Run Migrations

$ knex migrate:latest

Add --env=test to migrate your test database.

Seeds

Create Seeds

$ knex seed:make <examples>

Replace the function in seeds/dev/<examples>.js with your own seeds.d

Seed DB

$ knex seed:run

Requiring Necessary Modules into Express

The following lines may need their paths adjusted depending on where in the project they're used.

const environment = process.env.NODE_ENV || 'development';    // if something else isn't setting ENV, use development
const configuration = require('../knexfile')[environment];    // require environment's settings from knexfile
const database = require('knex')(configuration);              // connect to DB via knex using env's settings

You're ready to get devving!

Exactly what I needed, thanks.

If by chance in the connection section I want to pass a file that exports all the data. How could I do it?

Hey Lauren, just wanted to say thank you for posting this. Helped me solve my issue and create my first database with Postgres!

I'm finally able to deploy my API because of this

thank you very much

Thanks! That is exactly what I need! Connecting to postgresql would be a great addition to my project!

Thank you so much. I wish you successful deploying)

Hi Lauren thanks for your gist , this is what i exactly need !