// Connecting to database
public function connect() {
    require_once 'include/Config.php';
    // Connecting to mysql database
    $this->conn = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_DATABASE);
    $this-> conn->set_charset("utf8");
    // return database handler
    return $this->conn;
}

$stmt->bind_param("ssssssssssssssss", $name, $father_name, $gender, $age, $dob, $cnic, $phone_no, $address, $email, $encrypted_password, $salt, $roll_no, $session, $section, $semester, $shift);
    $result = $stmt->execute();
    $stmt->close();

create table users(
id int(11) primary key auto_increment,
/** unique_id varchar(23) not null unique, **/
name varchar(50) not null,
fahter_name varchar(50) not null,
gender varchar(7) not null,
age varchar(3) not null,
dob varchar(15) not null,
cnic varchar(100) not null,
phone_no varchar(100) not null unique,
address varchar(50) not null,
email varchar(100) not null unique,
encrypted_password varchar(80) not null,
salt varchar(10) not null,
roll_no varchar(50) not null,
session varchar(50) not null,
section varchar(2) not null,
semester varchar(2) not null,
shift varchar(50) not null,
created_at datetime,
updated_at datetime