Call to a member function query() on null with PDO - php

Question

I just checked all of the answers are available on stackoverflow,they are similar but not my answer exactly. So please don't take this post as duplicate.
these are my codes when I'm executing it say's
Fatal error: Call to a member function query() on null in
C:\wamp64\www\ourCMS\index.php on line 12
Here is my snippet :
<?php
class DB
{
private $dbHost;
private $dbName;
private $dbUser;
private $dbPass;
protected $con;
function set_db($host, $db, $user, $pass)
{
$this->dbHost = $host;
$this->dbName = $db;
$this->dbUser = $user;
$this->dbPass = $pass;
}
function connect()
{
$info = 'mysql:host='.$this->dbHost.';dbname='.$this->dbName;
try
{
$this->con = new PDO($info, $this->dbUser, $this->dbPass);
}
catch(PDOException $e)
{
print "Error Founds: ".$e->getMessage().PHP_EOL;
die();
}
}
}
// here is the place where i'm trying to use this actually
if (isset($_POST['submit']))
{
include('include/database.php');
$database = new DB;
$database->set_db("localhost", "ourcms", "root", "");
$conn = $database->connect();
$name = $_POST['nm'];
$query = "INSERT INTO testingpdo (name) VALUES ('$name')";
$data = $conn->query($query);
$result = $data->fetchAll(PDO::FETCH_ASSOC);
print_r($result);
}

Answer 1

You don't return nothing from DB::connect ($conn = $database->connect();). Add return $this->con; at the end of the function.
function connect()
{
$info = 'mysql:host='.$this->dbHost.';dbname='.$this->dbName;
try
{
$this->con = new PDO($info, $this->dbUser, $this->dbPass);
}
catch(PDOException $e)
{
print "Error Founds: ".$e->getMessage().PHP_EOL;
die();
}
return $this->con;
}