<?php

class MyDbConnectionClass {
  public function connect(){
      $conn = $this->createDbConnection();
      $this->setDbConnection($conn);
      return $conn;
  }

  protected function createDbConnection(){
      return mysql_connect("localhost");  
  }

  private function setDbConnection($conn){
      $this->dbConnection = $conn;
  }
  private $dbConnection;
}

class MyFooDotComDbConnectionClass extends MyDbConnectionClass {
  protected function createDbConnection(){
      return mysql_connect("foo.com");
  }
}

?>