<?php
defined('_JEXEC') or die('Restricted Access');
jimport('joomla.form.helper');
JFormHelper::loadFieldClass("list");

class JFormFieldHelloWorld extends JFormFieldList {

    protected $type = "HelloWorld";

    protected function getOptions()
    {
        $db = JFactory::getDbo();
        $query = $db->getQuery(true);
        $query->select("id, greeting");
        $query->from("#__helloworld");
        $db->setQuery($query->__toString());
        $messages = $db->loadObjectList();
        $options = array();
        if ($messages)
        {
            foreach ($messages as $message)
            {
                $options[] = JHtml::_('select.option', $message->id, $message->greeting);
            }
        }
        $options = array_merge(parent::getOptions(), $options);
        return $options;
    }
}

?>