Refrencing connection file in multiple PHP scripts - php

Question

I am having some trouble understanding how to correctly reference the following connection file in multiple PHP scripts.
DB Configuration File:
Config.php
/**
* Database config variables
*/
define("DB_HOST", "localhost");
define("DB_USER", "username");
define("DB_PASSWORD", "password");
define("DB_DATABASE", "dbName");
?>
Connection File:
DB_Connect.php
<?php
class DB_Connect {
private $conn;
// Connecting to database
public function connect() {
require_once 'include/Config.php';
// Connecting to mysql database
$this->conn = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_DATABASE);
// return database handler
return $this->conn;
}
}
?>
Connection Header of a PHP document:
How should the connection header for the following PDO script be written:
<?php
{
$options = [
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::ATTR_EMULATE_PREPARES => false,
];
$conn = new PDO("mysql:host=$hostdb;dbname=$namedb;charset=$charset", $userdb, $passdb, $options);
$stmt = $conn->prepare("SELECT `column1`
FROM `Table1` ");
$stmt->execute([]);
$row = $stmt->fetchAll(PDO::FETCH_ASSOC);
echo json_encode($row);
}
?>

Answer 1

First off, this class DB_Connect makes absolutely no sense. In theory it adds some abstract "abstraction" but in reality it's just useless piece of code. So just get rid of it.
Then create a file named pdo.php and add the following code (based on my How to connect to MySQL using PDO canonical example):
$host = '127.0.0.1';
$db = 'dbname';
$user = 'username';
$pass = 'password';
$charset = 'utf8mb4';
$options = [
\PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION,
\PDO::ATTR_DEFAULT_FETCH_MODE => \PDO::FETCH_ASSOC,
\PDO::ATTR_EMULATE_PREPARES => false,
];
$dsn = "mysql:host=$host;dbname=$db;charset=$charset";
try {
$pdo = new \PDO($dsn, $user, $pass, $options);
} catch (\PDOException $e) {
throw new \PDOException($e->getMessage(), (int)$e->getCode());
}
then just include this file in any script that requires a database interaction:
<?php
require $_SERVER['DOCUMENT_ROOT'].'/includes/pdo.php';
$stmt = $pdo->query("SELECT `column1` FROM `Table1` ");
$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
echo json_encode($rows);
Note that $_SERVER['DOCUMENT_ROOT'] stuff. it is used to make your file available from any directory. it is explained in my other article on the using correct filesystem paths

Answer 2

class DB_PDO_Connect {
private $db;
// Connecting to database
public function connect() {
if(!isset($this->db)){
require_once 'include/Config.php';
$this->db = new PDO("mysql:dbname=DB_DATABASE;host=DB_HOST;", DB_USER, DB_PASSWORD,
array(PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES \'UTF8\''));
$this->db->setAttribute(PDO::ATTR_CASE, PDO::CASE_NATURAL );
$this->db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$this->db->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING ); // debug
}
return $this->db;
}
}
use
$myPDO =new DB_PDO_Connect();
$conn=$myPDO->connect();
$stmt = $conn->prepare("SELECT `column1` FROM `Table1` ");
//...