<?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',
    );


    public function getCMSFields() {
        $fields = parent::getCMSFields();
        // change the label on the CMS UI
        $fields->renameField('Label', 'Drawer Header');
        $fields->renameField('URL', 'External URL');

        // need to change the label I_URL to Internal URL
        $fields->replaceField('I_URL', new TextField('I_URL', 'Internal URL'));

       // $iurl_field = $this->fieldByName('I_URL');
       // $iurl_field->setTitle('test');
        return $fields;
    }
}