<?php
class DrawerLink extends DataObject {
    public static $db = array(
        'Label' => 'Varchar(255)',
        // external URL
        'URL' => 'Varchar(255)',
        // internal URL
    );

    public static $has_one = array(
        'Drawer' => 'Drawer',
        'I_URL' => 'SiteTree',
        'Document' => 'File',
    );


    public function getCMSFields() {
        $fields = parent::getCMSFields();
        // change the label on the CMS UI
        $fields->renameField('URL', 'External URL');
        $fields->renameField('I_URLID', 'Internal URL');
        return $fields;
    }
}