mysql中php生成唯一ID

<?php

  //uniqid官方手册

  function create_guid($namespace = '') {     

     static $guid = '';

     $uid = uniqid("", true);

     $data = $namespace;

     $data .= $_SERVER['REQUEST_TIME'];

     $data .= $_SERVER['HTTP_USER_AGENT'];

     $data .= $_SERVER['REMOTE_ADDR'];

     $data .= $_SERVER['REMOTE_PORT'];

     $hash = strtoupper(hash('ripemd128', $uid . $guid . md5($data)));

     $guid = '{' .   

             substr($hash,  0,  8) . 

             '-' .

             substr($hash,  8,  4) .

             '-' .

             substr($hash, 12,  4) .

             '-' .

             substr($hash, 16,  4) .

             '-' .

             substr($hash, 20, 12) .

             '}';

     return $guid;

   }

?>