PDO supports data caching_PHP tutorial

/**
*Author: Chu Shi
* QQ: 345610000
​*/
class myPDO extends PDO
{
public $cache_Dir = null; //Cache directory
public $cache_expireTime = 7200; //Cache time, default is two hours

//Query with cache
public function cquery($sql)
{
//Cache storage directory
if ($this->cache_Dir == null || !is_dir($this->cache_Dir)) {
exit ("The cache directory is wrong!");
} else {
$this->cache_Dir = str_replace("", "/", $this->cache_Dir);
$FileName = trim($this->cache_Dir, "/") . '/' . urlencode(trim($sql)) . '.sql';
}
//Judge to generate cache
if (!file_exists($FileName) || time() - filemtime($FileName) > $this->cache_expireTime) {
If ($tmpRS = parent::query($sql)) {
$data = serialize($tmpRS->fetchAll());
Self::createFile($FileName, $data);
} else {
exit ("SQL syntax error
");
}
}
return $this->readCache($FileName);
}

//Read cache file
private static function readCache($FilePath)
{
if (is_file($FilePath) && $Data = file_get_contents($FilePath)) {
Return new cache_PDOStatement(unserialize($Data));
}
return false;
}

//Generate file
public static function createFile($FilePath, $Data = '')
{
if (file_put_contents($FilePath, $Data)) {
Return true;
} else {
Return false;
}
}
}
//Cache uses Statement class
class cache_PDOStatement
{
private $recordArr = array();
private $cursorId = 0;
private $recordCount = 0;

public function __construct($arr)
{
$this->recordArr = $arr;
$this->recordCount = count($arr);
}

//Return a record, move the pointer down one line
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);
}
}

//Return all results
public function fetchAll()
{
Return $this->recordArr;
}

//Single row and single column query
public function fetchColumn()
{
$tmpArr = current($this->recordArr);
return $tmpArr[0];
}
}

How to use
$db = new myPDO('mysql: host = localhost;dbname=news','newsadmin','123456');

$db->cache_Dir = "cache"; //Set the cache directory
$db->cache_expireTime = 7200; //Set cache time

$rs = $db->cquery("select * from news limit 0,10"); //Use cache query method cquery instead of query
while ($row = $rs->fetch()) {
echo $row["F_title"] . "
";
}

$rs = null;
$db = null;