protected static function changeSubPalettesToConditions()
    {
        $objDB = self::DB();

        // Create the table.
        if (!$objDB->tableExists('tl_metamodel_dcasetting_condition')) {
            $objDB->execute(
                'CREATE TABLE `tl_metamodel_dcasetting_condition` (
                `id` int(10) unsigned NOT NULL auto_increment,
                `pid` int(10) unsigned NOT NULL default \'0\',
                `settingId` int(10) unsigned NOT NULL default \'0\',
                `sorting` int(10) unsigned NOT NULL default \'0\',
                `tstamp` int(10) unsigned NOT NULL default \'0\',
                `enabled` char(1) NOT NULL default \'\',
                `type` varchar(255) NOT NULL default \'\',
                `attr_id` int(10) unsigned NOT NULL default \'0\',
                `comment` varchar(255) NOT NULL default \'\',
                `value` blob NULL,
                PRIMARY KEY  (`id`)
                )ENGINE=MyISAM DEFAULT CHARSET=utf8;'
            );
        }

        if ($objDB->tableExists('tl_metamodel_dcasetting', null, true)
            && $objDB->fieldExists('subpalette', 'tl_metamodel_dcasetting', true)
        ) {
            $subpalettes = $objDB->execute('SELECT * FROM tl_metamodel_dcasetting WHERE subpalette!=0');

            if ($subpalettes->numRows) {
                // Get all attribute names and setting ids.
                $attributes = $objDB
                    ->execute('
                        SELECT attr_id, colName
                        FROM tl_metamodel_dcasetting AS setting
                        LEFT JOIN tl_metamodel_attribute AS attribute
                        ON (setting.attr_id=attribute.id)
                        WHERE dcatype=\'attribute\'
                    ');

                $attr = array();
                while ($attributes->next()) {
                    $attr[$attributes->attr_id] = $attributes->colName;
                }

                $checkboxes = $objDB->execute('
                    SELECT *
                    FROM tl_metamodel_dcasetting
                    WHERE
                        subpalette=0
                        AND dcatype=\'attribute\'
                    ');

                $check = array();
                while ($checkboxes->next()) {
                    $check[$checkboxes->id] = $checkboxes->attr_id;
                }

                while ($subpalettes->next()) {
                    // Add property value condition for parent property dependency.
                    $data = array(
                        'pid' => 0,
                        'settingId' => $subpalettes->id,
                        'sorting' => '128',
                        'tstamp' => time(),
                        'enabled' => '1',
                        'type' => 'conditionpropertyvalueis',
                        'attr_id' => $check[$subpalettes->subpalette],
                        'comment' => sprintf(
                            'Only show when checkbox "%s" is checked',
                            $attr[$check[$subpalettes->subpalette]]
                        ),
                        'value' => '1',
                    );

                    $objDB
                        ->prepare('INSERT INTO tl_metamodel_dcasetting_condition %s')
                        ->set($data)
                        ->execute();

                    $objDB
                        ->prepare('UPDATE tl_metamodel_dcasetting SET subpalette=0 WHERE id=?')
                        ->execute($subpalettes->id);

                    $objDB
                        ->prepare('UPDATE tl_metamodel_dcasetting SET submitOnChange=1 WHERE id=?')
                        ->execute($subpalettes->subpalette);
                }
            }

            TableManipulation::dropColumn('tl_metamodel_dcasetting', 'subpalette', true);
        }
    }