在php中查找意图连接函数

Question

This is db.php file for connection of the MYSQL .I'm using 1.single instance of self shared among all instances 2.db connection config vars 3.This method must be static, and must return an instance of the object if the object.does not already exist. 4.The clone and wakeup methods prevents external instantiation of copies of the Singleton class,thus eliminating the possibility of duplicate objects.

<?php
    include('config.php');
    class db extends mysqli {


        // single instance of self shared among all instances
        private static $instance = null;


        // db connection config vars
        private $user = DBUSER;
        private $pass = DBPWD;
        private $dbName = DBNAME;
        private $dbHost = DBHOST;

        //This method must be static, and must return an instance of the object if the object
        //does not already exist.
        public static function getInstance() {
        if (!self::$instance instanceof self) {
                self::$instance = new self;
        }
            return self::$instance;
        }

        // The clone and wakeup methods prevents external instantiation of copies of the Singleton class,
        // thus eliminating the possibility of duplicate objects.
        public function __clone() {
       trigger_error('Clone is not allowed.', E_USER_ERROR);
        }
        public function __wakeup() {
        trigger_error('Deserializing is not allowed.', E_USER_ERROR);
        }

        private function __construct() {
        parent::__construct($this->dbHost, $this->user, $this->pass, $this->dbName);
        if (mysqli_connect_error()) {
            exit('Connect Error (' . mysqli_connect_errno() . ') '
                    . mysqli_connect_error());
        }
        parent::set_charset('utf-8');

       }
       public function dbquery($query)
        {
            if($this->query($query))
            {
                return true;
            }

        }
        public function get_result($query) 
        {
            $result = $this->query($query);
            if ($result->num_rows > 0){
                while ($row = $result->fetch_assoc()) 
                {
                    $rows[] = $row;     
                }
            return $rows;
            } else
            return null;


        }
    }


    ?>

This is inserting cording with Escape user inputs for security

<?php

    $Institute_Name = mysqli_real_escape_string($conn, $_REQUEST['Institute_Name']);
    $Institute_Address = mysqli_real_escape_string($conn, $_REQUEST['Institute_Address']);

?>

i need how can i call $conn from instance

$conn = getInstance();

I try this.This is not working i need it for inserting code

$query= "INSERT INTO `institute` ( Institute_Name, Institute_Address, ) VALUES ('$Institute_Name', '$Institute_Address')";

Answer 1

you should use

$conn = db::getInstance();