NigelEarle

Migrations & Seeding

What are migrations??

Migrations are a way to make database changes or updates, like creating or dropping tables, as well as updating a table with new columns with constraints via generated scripts. We can build these scripts via the command line using knex command line tool.

To learn more about migrations, check out this article on the different types of database migrations!

Creating/Dropping Tables

NigelEarle

const cluster = require('cluster');
const http = require('http');
const numCPUs = require('os').cpus().length;


if (cluster.isMaster) {
  console.log(`Master ${process.pid} is running`);

  // Fork workers.
  for (let i = 0; i < numCPUs; i++) {

NigelEarle

Knex Setup Guide

Create your project directory

Create and initialize your a directory for your Express application.

$ mkdir node-knex-demo
$ cd node-knex-demo
$ npm init

NigelEarle

const arr = ['mom', 'dad', 'abcde', 'racecar', 'momom'];

function namePalindrome(arr) {
  return arr.filter((curr, idx, arr) => {
    const splitArr = curr.split('');
    const reversedString = splitArr.reduceRight((prev, curr) => ( prev + curr ), '');
    if (curr === reversedString) return curr;
  })
}

NigelEarle

# Created by https://www.gitignore.io

.Python
bin/
include/
lib/
pip-selfcheck.json
*.py[cod]
*.DS_Store

NigelEarle

const cleanRoom = () => {
  return new Promise((resolve, reject) => {
    resolve('Clean room,');
  });
}

const takeTrash = (message) => {
  return new Promise((resolve, reject) => {
    resolve(message + ' Take out trash,');
  })

NigelEarle

if (!!window.EventSource) {
  const source = new EventSource('/api/bubble-sort');
  source.onmessage = (e) => {
    const data = JSON.parse(e.data);
    // data parsed
  };

  source.onopen = () => {
    console.log('connected!');
  };

NigelEarle

for (var i = 0;i < 10;i++) {
   (function(i) {
        setTimeout(function(){
            console.log(i);
        }, 1000 * i);
   })(i);
}

NigelEarle

/**
 * @flow
 */

import React from 'react';
import {
  AppRegistry,
  AsyncStorage,
  Button,
  StyleSheet,

NigelEarle

const got = require('got');
const querystring = require('querystring');
const Promise = require('bluebird');
let url = [
           "https://newsapi.org/v1/articles?source=cnn&sortBy=top&apiKey=9f3b3102ab704b7c9a874ee92cdb288f",
           "https://newsapi.org/v1/articles?source=abc-news-au&sortBy=top&apiKey=9f3b3102ab704b7c9a874ee92cdb288f",
           "https://newsapi.org/v1/articles?source=associated-press&sortBy=top&apiKey=9f3b3102ab704b7c9a874ee92cdb288f",
           "https://newsapi.org/v1/articles?source=bbc-news&sortBy=top&apiKey=9f3b3102ab704b7c9a874ee92cdb288f",
           "https://newsapi.org/v1/articles?source=bloomberg&sortBy=top&apiKey=9f3b3102ab704b7c9a874ee92cdb288f",
           "https://newsapi.org/v1/articles?source=business-insider&sortBy=top&apiKey=9f3b3102ab704b7c9a874ee92cdb288f",