How to use PDO connection in other classes?

by
  • your current class is rather useless. It would make sense to create a database wrapper if it adds some extra functionality to PDO. But given its current code, better to use vanilla PDO instead.
  • Either way, create a single $db instance from either vanilla PDO or your database class.
  • pass it as a constructor parameter into every class that needs a database connection

database.php:

<?php
$host="127.0.0.1";
$db   = 'test';
$user="root";
$pass="";
$charset="utf8";

$dsn = "mysql:host=$host;dbname=$db;charset=$charset";
$opt = [
    \PDO::ATTR_ERRMODE            => \PDO::ERRMODE_EXCEPTION,
    \PDO::ATTR_DEFAULT_FETCH_MODE => \PDO::FETCH_ASSOC,
    \PDO::ATTR_EMULATE_PREPARES   => false,
];
$pdo = new \PDO($dsn, $user, $pass, $opt);

user.php

<?php
class User {
    /* Properties */
    private $conn;

    /* Get database access */
    public function __construct(\PDO $pdo) {
        $this->conn = $pdo;
    }

    /* List all users */
    public function getUsers() {
        return $this->conn->query("SELECT username, usermail FROM user")->fetchAll();
    }
}

app.php

include 'database.php';
$user = new User($pdo);
$list = $user->getUsers();

foreach($list as $test) {
    echo $test["username"],"\n";
}

output:

username_foo
username_bar
username_baz

Check out my (The only proper) PDO tutorial for more PDO details.

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