class TalkPHP_UniqueKeyGenerator
{
    public static function make()
    {
        $aChars = range('A', 'Z');
        $aRange = array_merge($aChars, range(0, 9));
        
        shuffle($aRange);
        
        $aSegments = array
        (
            implode('', array_slice($aRange, 0, 8)),
            $aChars[rand(0, count($aChars) - 1)]
        );
        
        $szKey = implode('', $aSegments);
        
        mysql_query(sprintf("INSERT INTO report (hash) VALUES ('%s')", $szKey));
        $iPrimaryKey = mysql_insert_id();
        mysql_query("UPDATE report SET hash = CONCAT(hash, last_insert_id()) WHERE id = last_insert_id()");
        
        return $szKey . $iPrimaryKey;
    }
    
    public static function get($szKey)
    {
        preg_match('~.+?(\d+)$~i', $szKey, $aMatches);
        
        if (empty($aMatches))
        {
            return false;
        }
        
        $pResult = mysql_query(sprintf("SELECT * FROM report WHERE id = %d", (int) $aMatches[1]));
        $aResult = mysql_fetch_row($pResult);
        
        return isset($aResult[0]) ? $aResult[0] : false;
    }
}
    
mysql_connect('localhost', 'Username', 'Password');
mysql_select_db('Database');

$szGeneratedKey = TalkPHP_UniqueKeyGenerator::make();
printf('Incident Report ID Set: %s<br />', $szGeneratedKey);
printf('Incident Report ID Get: %d (PK)', TalkPHP_UniqueKeyGenerator::get($szGeneratedKey));

CREATE TABLE `report` (
  `id` int(10) UNSIGNED NOT NULL AUTO_INCREMENT,
  `hash` varchar(16) NOT NULL,
  PRIMARY KEY  (`id`),
  UNIQUE KEY `hash` (`hash`)
) ENGINE=InnoDB AUTO_INCREMENT=22 DEFAULT CHARSET=latin1;