这是我的控制器，其中用户名检查与电子邮件id，我有这个登录的注册区。我的需要是采取会话数据，包括会话id从这个代码可以有人请帮助整理这一点吗？

控制器

public function login(){
    
    $this->form_validation->set_rules('username', 'Username', 'required');
    $this->form_validation->set_rules('password', 'Password', 'required|min_length[5]');
    
    if($this->form_validation->run() == TRUE){
        
        $username = $_POST['username'];
        $password = md5($_POST['password']);
        
        //check user in db
        
        //session details for email and phone
        
        $this->db->select('*');
        $this->db->from('users');
        
        $query1 = $this->db->get();
        $sess = $query1->row();
        
        $this->db->select('*');
        $this->db->from('users');
        $this->db->where(array('email'=>$username, 'password'=>$password));
        $query = $this->db->get();
        
        $user = $query->row();
        
        
        //if user exists 
        if($user->email){
            //temp messAGE
            $this->session->set_flashdata("success",'you are logged in');
             
            //SET session variables
            $_SESSION['user_logged']= TRUE;
            $_SESSION['username']= $user->username;
            
            //redirection to profile page
            
            redirect("user/profile", "refresh");
        }
        else{
             $this->session->set_flashdata("error",'No Such Accounts found or please check username and password');
             redirect("home/index", "refresh");
         }
     }
     
    $this->load->view('login');
}