title: How to use sessions in PDO?
body: <p>I am still redoing and getting rid of old mysql_* commands in my code. I tried to transfer my session login form old code and this is what I got so far:</p>
  
  <pre><code>  public function login($user, $password)
    {
      if (!empty($user) &amp;&amp; !empty($password))
      {    
        $password = $web-&gt;doHash($user, $password); // in this function is (return sha1(strtoupper($user).':'.strtoupper($password))
        $stmt = $db_login-&gt;prepare("SELECT * FROM account WHERE username=:user AND pass_hash=:password");
        $stmt-&gt;bindValue(':user', $user, PDO::PARAM_STR);
        $stmt-&gt;bindValue(':password', $password, PDO::PARAM_STR);
        $stmt-&gt;execute();
        $rows = $stmt-&gt;rowCount();
  
        if ($rows &gt; 0)      
        {    
          $results_login = $stmt-&gt;fetch(PDO::FETCH_ASSOC);
          $_SESSION['user_name'] = $results_login['username'];
          $_SESSION['user_id'] = $results_login['id'];  
          return true;
        }
        else
        {
          return false;
        }
      }
      else
      {
        return false;
      }
    }
  </code></pre>
  
  <p>After that I am using checks if user logged on site:</p>
  
  <pre><code>  public function isLogged()
    {
      return (!empty($_SESSION['user_id']) &amp;&amp; !empty($_SESSION['user_name']));
    }
  </code></pre>
  
  <p>But it seems - this function returns always empty because $_SESSION does not exists in PDO? And of course logout is used in this form on my sites:</p>
  
  <pre><code>  public function logout()
    { 
        unset($_SESSION['user_id']);
        unset($_SESSION['user_name']);       
    } 
  </code></pre>
  
  <p>But I think PDO has different way of handling session? I did not find any so what is it can i somehow add $_SESSION in PDO withou changing code much? </p>
  
  <p>I am using variables <code>$_SESSION['user_name']</code> and <code>$_SESSION['user_id']</code> in all over my web project.</p>
  
  <p>Summary:</p>
  
  <p>1) How to use sessions in PDO correctly?</p>
  
  <p>2) What is difference between using <code>$stmt-&gt;fetch(PDO::FETCH_ASSOC);</code> and <code>$stmt-&gt;fetchAll();</code></p>
  
  <p>Thank you.</p>