public function resetFields(array $fields) {
		$defaults = $this->defaults();
		foreach ($fields as $field) {
			unset($this->fieldsCache[$field]);
			unset($this->saveCsd[$field]);
			if (isset($defaults[$field]))
				$this->set($field,$defaults[$field]);
			else {
				$this->set($field,NULL);
			}
		}
	}