is there any reasone why the following doesn't work?

$connection=oci_connect('landon', 'xxxxxxx',$db)
session_start();
$_SESSION['connection'] = $connection;
..
..
..

$connection = $_SESSION['connection'] ;    shows nothing!

My program allows many operations on a table re-entering at the top
and deciding what option to do next.

I don't want to keep logging into Oracle but use the previous connection