Home  >  Article  >  php教程  >  PDO支持数据缓存

PDO支持数据缓存

WBOY
WBOYOriginal
2016-06-13 10:09:582328browse

/**
 * 作者:初十
 * QQ:345610000
 */
class myPDO extends PDO
{
 public $cache_Dir = null; //缓存目录
 public $cache_expireTime = 7200; //缓存时间,默认两小时
 
 //带缓存的查询
 public function cquery($sql)
 {
  //缓存存放总目录
  if ($this->cache_Dir == null || !is_dir($this->cache_Dir)) {
   exit ("缓存目录有误!");
  } else {
   $this->cache_Dir = str_replace("\", "/", $this->cache_Dir);
   $FileName = trim($this->cache_Dir, "/") . '/' . urlencode(trim($sql)) . '.sql';
  }
  //判断生成缓存
  if (!file_exists($FileName) ||  time() - filemtime($FileName) > $this->cache_expireTime) {
   if ($tmpRS = parent::query($sql)) {
    $data = serialize($tmpRS->fetchAll());
    self::createFile($FileName, $data);
   } else  {
    exit ("SQL语法错误
");
   }
  }
  return $this->readCache($FileName);
 }
 
 //读缓存文件
 private static function readCache($FilePath)
 {
  if (is_file($FilePath) && $Data = file_get_contents($FilePath)) {
   return new cache_PDOStatement(unserialize($Data));
  }
  return false;
 }
 
 //生成文件
 public static function createFile($FilePath, $Data = '')
 {
  if (file_put_contents($FilePath, $Data)) {
   return true;
  } else {
   return false;
  }
 }
}
//缓存用到Statement类
class cache_PDOStatement
{
 private $recordArr = array();
 private $cursorId = 0;
 private $recordCount = 0;
 
 public function __construct($arr)
 {
  $this->recordArr = $arr;
  $this->recordCount = count($arr);
 }
 
 //返回一条记录,指针下移一行
 public function fetch()
 {
  if ($this->cursorId == $this->recordCount) {
   return false;
  } else if ($this->cursorId == 0) {
   $this->cursorId++;
   return current($this->recordArr);
  } else {
   $this->cursorId++;
   return next($this->recordArr);
  }
 }
 
 //返回全部结果
 public function fetchAll()
 {
  return $this->recordArr;
 }
 
 //单行单列查询
 public function fetchColumn()
 {
  $tmpArr = current($this->recordArr);
  return $tmpArr[0];
 }
}

使用方法
$db = new myPDO('mysql: host = localhost;dbname=news','newsadmin','123456');

$db->cache_Dir = "cache"; //设置缓存目录
$db->cache_expireTime = 7200; //设置缓存时间

$rs = $db->cquery("select * from news limit 0,10"); //用缓存查询方法cquery代替query
while ($row = $rs->fetch()) {
 echo $row["F_title"] . "
";
}

$rs = null;
$db = null;

Statement:
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Previous article:php 导出csv文件程序Next article:判断WebSERVER类型