PHP script to connect to database using PDO library/class

pdo-connect.php

<?PHP

$config = [
  'DB_HOSTNAME' => 'localhost',
  'DB_USERNAME' => 'root',
  'DB_PASSWORD' => 'rootpassword',
  'DB_DATABASE' => 'dummy_database'
];

$dsn = "mysql:host={$config['DB_HOSTNAME']};dbname={$config['DB_DATABASE']};charset=utf8mb4";

$options = [
  PDO::ATTR_EMULATE_PREPARES   => false, // turn off emulation mode for "real" prepared statements
  PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION, // turn on errors in the form of exceptions
  PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC, // make the default fetch be an associative array
];

try {
  $this->conn = new PDO($dsn, $config['DB_USERNAME'], $config['DB_PASSWORD'], $options);
} catch (Exception $e) {
  error_log($e->getMessage());
  exit('Something weird happened'); // something a user can understand
}