<?php
/**
 * Magento
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Open Software License (OSL 3.0)
 * that is bundled with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://opensource.org/licenses/osl-3.0.php
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@magentocommerce.com so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade Magento to newer
 * versions in the future. If you wish to customize Magento for your
 * needs please refer to http://www.magentocommerce.com for more information.
 *
 * @category    Mage
 * @package     Mage_Downloadable
 * @copyright   Copyright (c) 2012 Magento Inc. (http://www.magentocommerce.com)
 * @license     http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 */

$installer = $this;
/* @var $installer Mage_Catalog_Model_Resource_Eav_Mysql4_Setup */

$installer->startSetup();

$fieldList = array(
    'price',
    'special_price',
    'special_from_date',
    'special_to_date',
    'minimal_price',
    'cost',
    'tier_price',
    'weight',
    'tax_class_id'
);

// make these attributes applicable to downloadable products
foreach ($fieldList as $field) {
    $applyTo = explode(',', $installer->getAttribute(Mage_Catalog_Model_Product::ENTITY, $field, 'apply_to'));
    if (!in_array('downloadable', $applyTo)) {
        $applyTo[] = 'downloadable';
        $installer->updateAttribute(Mage_Catalog_Model_Product::ENTITY, $field, 'apply_to', join(',', $applyTo));
    }
}

$installer->endSetup();