<?php
function getDb() {
  static $pdo = null;
  
  if ($pdo === null) {
    define('DB_HOST', "db");
    define("DB_PORT", "3306");
    define('DB_USER', "user");
    define('DB_PASSWORD', "password");
    define('DB_NAME', "trainee_db");
    
    $dsn = "mysql:host=" . DB_HOST . ";port=" . DB_PORT . ";dbname=" . DB_NAME . ";charset=utf8mb4";
    
    $pdo = new PDO($dsn, DB_USER, DB_PASSWORD);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
  }
  
  return $pdo;
}
?>