protected function convertNamedParams($parts, $args) {
		if (empty($args)) return array($parts, $args);
		$params = array();
		$pos = 0;
		foreach ($parts as &$part) {
			if (preg_match('/:\w+/i', $part, $match)) {
				if (!array_key_exists($match[0],$args))
					trigger_error(sprintf(self::E_MISSINGBINDKEY,
						$match[0]),E_USER_ERROR);
				$part = str_replace($match[0], '?', $part);
				$params[] = $args[$match[0]];
			} elseif (is_int(strpos($part, '?')))
				$params[] = $args[$pos++];
			unset($part);
		}
		return array($parts, $params);
	}