Question

So I’ve found a method which looked nice to me: http://www.php.net/manual/en/class.pdo.php#97682

Requires PHP 5.3 but my host only supports 5.2 🙁

So what method should I use for PDO, where it only connects to the database when needed?
And reuses the same connection?

Answer 1

Use a procedural singleton for readability:

 function db() {
      static $conn;
      if (!isset($conn)) {
           $conn = new PDO("sqlite:/tmp/db");
      }
      return $conn;
 }

This simplifies the use to for example:

 $rows = db()->query("SELECT * FROM all")->fetchAll();