PDO query like always - php

Question

In my class 'uzytkownikclass.php' i have a variable which is called '$handler'. That variable store connection with my MySQL database. Before, i created few methods that query database for data. Those functions are working fine. But i created a new method called 'hasRole' which check user role (Administator, moderator etc). But i have a error, PDO is new for me and i can not fix this alone.
Here is my code:
public function hasRole()
{
$email=$_SESSION['email_session'];
$stmt = $this->handler->prepare("SELECT COUNT(*) FROM users INNER JOIN rolausera ON users.id = idusera INNER JOIN rola ON idroli = rola.id WHERE email = :email AND rola.id = :rola");
$stmt->bindValue(':email',$email, PDO::PARAM_STR);
$stmt->bindValue(':rola',$rola, PDO::PARAM_STR);
$stmt->execute();
$result = $stmt->fetchAll();
if($result[0]>0)
{
return TRUE;
}
else
{
return FALSE;
}
}
Here is an error:
Fatal error: Call to a member function prepare() on null in D:\Programy\XAMPP\htdocs\logic\uzytkownikclass.php on line 120
As i said before, i have working methods:
$stmt = $this->handler->prepare("SELECT id, login, email, haslo FROM users WHERE email=:email1 ");
$stmt->execute(array(':email1'=>$email1));
$userRow=$stmt->fetch(PDO::FETCH_ASSOC);
and here is my connection method:
public $handler;
public function connection()
{
$this->handler = new PDO('mysql:host=localhost;dbname=blog', 'root', '',array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES 'utf8'"));
if($this->handler==false)
{
echo 'Blad';
}
}
I tried to delete relation in query and use simple 'SELECT * FROM user' and i had same error.
Greetings.

Answer 1

The question is: did you call the connection() method before calling the hasRole(), or perhaps you closed the connection somewhere in your code? Anyway, I would check in all methods, that try to query the database, if the connection is established and call the connection() method if not. Php's is_null() function helps determining if a variable has been set. I would also check if $handle is false.

Answer 2

i think it's a problem with PHP 5.6 [Beta].
Check your active PHP version, if you have PHP 5.6 [Beta], change to 5.4.
I haved the same problem, a class for connection with PDO working fine, and without changes into the code, this error: Fatal error: Call to a member function prepare() on null in...
For experience, when i have these errors, i see into my PHP version. On my case the hosting changes the PHP version without advise :(
See: PHP bugs