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,  ,  ) .
             '-' .
             substr($hash,  ,  ) .
             '-' .
             substr($hash, ,  ) .
             '-' .
             substr($hash, ,  ) .
             '-' .
             substr($hash, , ) .
             '}';
     return $guid;
   }
?>