code-boxx/0-JS-CONNECT-DB.MD

## 0-JS-CONNECT-DB.MD

      
    Raw
  

              0-JS-CONNECT-DB.MD
            
          
    JAVASCRIPT CONNECT TO DATABASE

https://code-boxx.com/connect-database-javascript/
LICENSE

Copyright by Code Boxx
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

  
## 1a-dummy.sql
CREATE TABLE `users` (
  `user_id` bigint(20) NOT NULL,
  `user_name` varchar(255) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

INSERT INTO `users` (`user_id`, `user_name`) VALUES
(1, 'Joe Doe'),
(2, 'Jon Doe'),
(3, 'Joy Doe');

ALTER TABLE `users`
  ADD PRIMARY KEY (`user_id`),
  ADD KEY `user_name` (`user_name`);

ALTER TABLE `users`
  MODIFY `user_id` bigint(20) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=4;

## 1b-database.php
<?php
// (A) SETTINGS - CHANGE TO YOUR OWN !
error_reporting(E_ALL & ~E_NOTICE);
define("DB_HOST", "localhost");
define("DB_NAME", "test");
define("DB_CHARSET", "utf8mb4");
define("DB_USER", "root");
define("DB_PASSWORD", "");

// (B) CONNECT TO DATABASE
$pdo = new PDO(
  "mysql:host=".DB_HOST.";dbname=".DB_NAME.";charset=".DB_CHARSET,
  DB_USER, DB_PASSWORD, [
  PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
  PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC
]);

// (C) GET USERS
$stmt = $pdo->prepare("SELECT * FROM `users`");
$stmt->execute();
$users = $stmt->fetchAll();
foreach ($users as $u) {
  printf("<div>[%u] %s</div>", $u["user_id"], $u["user_name"]);
}

// (D) CLOSE DATABASE CONNECTION
$pdo = null;
$stmt = null;

## 1c-javascript.html
<!DOCTYPE html>
<html>
  <head>
    <title>AJAX Demo</title>
  </head>
  <body>
    <!-- (A) LIST USERS HERE -->
    <div id="demo"></div>

    <!-- (B) FETCH USERS VIA AJAX -->
    <script>
    // NOTE: RUN WITH HTTP://, NOT FILE://
    window.addEventListener("load", () => {
      fetch("1b-database.php", { method: "POST" })
      .then(res => res.text())
      .then(txt => document.getElementById("demo").innerHTML = txt);
    });
    </script>
  </body>
</html>

## 2-node-db.js
// (A) LOAD DB MODULE
const mysql = require("mysql");

// (B) CREATE CONNECTION - CHANGE TO YOUR OWN !
const db = mysql.createConnection({
  host: "localhost",
  user: "root",
  password: "",
  database: "test"
});
db.connect(err => {
  if (err) { throw err; }
  console.log("DB connection OK");
});

// (C) QUERY
db.query("SELECT * FROM `users`", (err, results) => {
  if (err) { throw err; }
  console.log(results);
});

## 3-localstorage.html
<!DOCTYPE html>
<html>
  <head>
    <title>Localstorage Demo</title>
    <script>
    // (A) DATA OBJECT
    var user = {
      name : "Jon Doe",
      email : "jon@doe.com"
    };

    // (B) STORE IN LOCAL STORAGE
    // note: json encode
    localStorage.setItem("User", JSON.stringify(user));

    // (C) RETRIEVE
    // note: json decode
    user = localStorage.getItem("User");
    user = JSON.parse(user);
    console.log(user);
    </script>
  </head>
  <body></body>
</html>
	CREATE TABLE `users` (
	`user_id` bigint(20) NOT NULL,
	`user_name` varchar(255) NOT NULL
	) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

	INSERT INTO `users` (`user_id`, `user_name`) VALUES
	(1, 'Joe Doe'),
	(2, 'Jon Doe'),
	(3, 'Joy Doe');

	ALTER TABLE `users`
	ADD PRIMARY KEY (`user_id`),
	ADD KEY `user_name` (`user_name`);

	ALTER TABLE `users`
	MODIFY `user_id` bigint(20) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=4;
	<?php
	// (A) SETTINGS - CHANGE TO YOUR OWN !
	error_reporting(E_ALL & ~E_NOTICE);
	define("DB_HOST", "localhost");
	define("DB_NAME", "test");
	define("DB_CHARSET", "utf8mb4");
	define("DB_USER", "root");
	define("DB_PASSWORD", "");

	// (B) CONNECT TO DATABASE
	$pdo = new PDO(
	"mysql:host=".DB_HOST.";dbname=".DB_NAME.";charset=".DB_CHARSET,
	DB_USER, DB_PASSWORD, [
	PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
	PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC
	]);

	// (C) GET USERS
	$stmt = $pdo->prepare("SELECT * FROM `users`");
	$stmt->execute();
	$users = $stmt->fetchAll();
	foreach ($users as $u) {
	printf("<div>[%u] %s</div>", $u["user_id"], $u["user_name"]);
	}

	// (D) CLOSE DATABASE CONNECTION
	$pdo = null;
	$stmt = null;
	<!DOCTYPE html>
	<html>
	<head>
	<title>AJAX Demo</title>
	</head>
	<body>
	<!-- (A) LIST USERS HERE -->
	<div id="demo"></div>

	<!-- (B) FETCH USERS VIA AJAX -->
	<script>
	// NOTE: RUN WITH HTTP://, NOT FILE://
	window.addEventListener("load", () => {
	fetch("1b-database.php", { method: "POST" })
	.then(res => res.text())
	.then(txt => document.getElementById("demo").innerHTML = txt);
	});
	</script>
	</body>
	</html>
	// (A) LOAD DB MODULE
	const mysql = require("mysql");

	// (B) CREATE CONNECTION - CHANGE TO YOUR OWN !
	const db = mysql.createConnection({
	host: "localhost",
	user: "root",
	password: "",
	database: "test"
	});
	db.connect(err => {
	if (err) { throw err; }
	console.log("DB connection OK");
	});

	// (C) QUERY
	db.query("SELECT * FROM `users`", (err, results) => {
	if (err) { throw err; }
	console.log(results);
	});