praise.php

<?php 
class Conmysql{
	public $servername;
	public $username;
	public $password;
	public $dbname;
	public $con = '';
	public function __construct($servername,$username,$password,$dbname){
		$this->servername = $servername;
		$this->username = $username;
		$this->password = $password;
		$this->dbname = $dbname;
	}
	public function getConnection(){
		try {
		    $dsn = "mysql:host=$this->servername;dbname=$this->dbname;";
		    $this->con = new PDO($dsn,$this->username,$this->password);
		}
		catch(PDOException $e)
		{
		    echo $e->getMessage();
		}
	}
	public function updateData($sql){
		if($this->con == null){
			$this->getConnection();
		}
		header('content-type:application/json;charset=utf8');
		$res = $this->con->exec($sql);
		$arr = array('result'=>$res);
		echo json_encode($arr);
		$this->closeCon();
	}
	public function closeCon(){
		$this->con = null;
	}
}
/**
* 
*/
class realCon extends Conmysql
{
	public function __construct($servername,$username,$password,$dbname){
		parent::__construct($servername,$username,$password,$dbname);
	}
	public function updateRealData(){
		$sql = "UPDATE user SET num = num+1 WHERE id = 1";
		$this->updateData($sql);
	}
}
$praiseConn = new realCon('localhost','root','123456','my');
$praiseConn->updateRealData();

?>