<?php

$host = "db hostname";
$dbname = "db name";
$user = "db username";
$pass = "db password";
$charset = "UTF8MB4"; // if your db does not use CHARSET=UTF8MB4, you should probably be fixing that

$dsn = "mysql:host={$host};dbname={$dbname};charset={$charset}";

$options = [
  PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, // highly recommended
  PDO::ATTR_EMULATE_PREPARES => false // ALWAYS! ALWAYS! ALWAYS!
];

try {
  $pdo = new PDO( $dsn, $user, $pass, $options );

  // now $pdo is ready for use!

} catch ( PDOException $e ) {
  // always catch PDOExceptions.
  // If there's a problem here, the error message will probably contain your DB password.

  // log the error.
  // during development, if your server is not public, you can display the message instead if you prefer.
  error_log( $e->getMessage() );
}