如何在php项目中实现一个面包屑导航功能

--
-- 表的结构 `tp_likecate`
--

CREATE TABLE IF NOT EXISTS `tp_likecate` (
 `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
 `catename` varchar(24) NOT NULL,
 `path` varchar(10) NOT NULL,
 `fullpath` varchar(20) NOT NULL,
 PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=9 ;

--
-- 转存表中的数据 `tp_likecate`
--

INSERT INTO `tp_likecate` (`id`, `catename`, `path`, `fullpath`) VALUES
(1, '手机', '', ',1'),
(2, '功能手机', '1', '1,2'),
(3, '老人手机', '1,2', '1，2，3'),
(4, '儿童手机', '1,2', '1,2,4'),
(5, '智能手机', '1', '1,5'),
(6, 'android手机', '1,5', '1,5,6'),
(7, 'IOS手机', '1,5', '1,5,7'),
(8, 'WinPhoto手机', '1,5', '1,5,8');

<&#63;php 
$db_host = 'localhost';
$db_user = 'root';
$db_password = '';
$db_name = 'test';
$con = mysql_connect($db_host, $db_user, $db_password) or die(mysql_error());
mysql_select_db($db_name, $con) or die(mysql_error());
mysql_query('set names utf8') or die(mysql_error());
&#63;>

function likecate($path='') {
  // concat() 连接字段
  $sql = "select id,catename,path, concat(path,',',id) as fullpath from tp_likecate order by fullpath asc";
  $res = mysql_query($sql);
  $result = array();
  while($row=mysql_fetch_assoc($res)) {
    $deep = count(explode(',', trim($row['fullpath'], ','))); // explode字符串转换为数组 implode数组转换为字符串
    $row['catename'] = @str_repeat('  ', $deep).'|--'.$row['catename'];
    $result[] = $row;
  }
  return $result;
}

// 简单输出
$res = likecate();

echo "<select name='cate'>";
foreach($res as $key=>$val) {
  echo "<option>{$val['catename']}</option>";
}
echo "</select>";
echo "<br />";

// 封装方法
function getPathCate($cateid) {
  $sql = "select *,concat(path, ',',id) fullpath from tp_likecate where id = $cateid";
  $res = mysql_query($sql);
  $row = mysql_fetch_assoc($res);
  $ids = $row['fullpath'];
  $sql = "select * from tp_likecate where id in($ids) order by id asc";
  $res = mysql_query($sql);
  $result = array();
  while($row = mysql_fetch_assoc($res)) {
    $result[] = $row;
  }
  return $result;
}

// 加上了链接的参数
function displayCatePath($cateid,$link='cate.php&#63;cid=') { // 也可以组装
  $res = getPathCate($cateid);
  $str = '';
  foreach($res as $k=>$v) {
    $str.= "<a href='{$link}{$v['id']}'>{$v['catename']}</a> > ";
  }
  return $str;
}
echo displayCatePath(4);