Mage, getting standard db connection

gistfile1.php

// instead of the following:

            // db variables
            $dsn = 'the dsn hard coded';
            $username = 'username hard coded';
            $password = 'password hard coded';

            // try to connect to the db
            try {
                $db = new PDO($dsn, $username, $password);
                $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                $db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
            } catch(PDOException $e) {
                die('Could not connec to to the database.<br />');
            }

            // create the statement handle
            $sth = $db->prepare("INSERT INTO newsletter_codes (email_address, discount_code) values (:email_address, :coupon_code)");
            
            // bind the parameters
            $sth->bindParam(':email_address', $_GET['email']);
            $sth->bindParam(':coupon_code', $coupon_code);

            // execute!
            $sth->execute();

// You can simply do the following
            
            $db = Mage::getSingleton('core/resource')->getConnection('core_write');
            $query = "INSERT INTO newsletter_codes (email_address, discount_code) values (:email_address, :coupon_code)";
            $params = array(
                'email_address' => $_GET['email'],
                'coupon_code' => $coupon_code
                );

            $db->query($query, $params);