Template::modifyTabletDataBeforeSave

protected function modifyTabletDataBeforeSave($data)
{
	// move 0 to null in PARENT_ID to avoid constraint and query problems
	// todo: move PARENT_ID and other "foreign keys" to the unique way of keeping absense of relation: null, 0 or ''
	if(array_key_exists('PARENT_ID', $data))
	{
		$data['PARENT_ID'] = intval($data['PARENT_ID']);
		if(!intval($data['PARENT_ID']))
		{
			$data['PARENT_ID'] = null;
		}
	}

	return $data;
}