PHP会话变量未定义

I have this session variable which i am trying to set to an access level when the users logs in with this:

 $accessquery = mysql_query("SELECT roleid FROM person WHERE email = '". $email ."'");
 $access = mysql_fetch_array($accessquery);

 $_SESSION['Access'] = $access;

However it says that 'Access' is undefined, what is the problem?

EDIT*

if (($_SESSION['Access']) == "2")

Error appears here

EDIT*

Session Start has been called.

Two possibilities here :

1. Start the session by using session_start(); at the begining of page.

2. use the following code:

   $accessquery = mysqli_query($conn, "SELECT roleid FROM person WHERE email = '". $email ."'", mysqli_store_result($conn));
   
   $access = mysqli_fetch_row($accessquery);
   
   $_SESSION['Access'] = $access[0];
   

To figure out what's going on, I recommend you to use

print_r($any_variable);

See http://php.net/print_r

Did you call session_start();?

Try to debug your code with just a fixed value: $_SESSION["Test"]="test"; and then do a var_dump($_SESSION);