Setting a session in steps - php

Question

Is it possible to set multiple session elements to the same session at different times? I have 2 classes and each class should set 2 session elements. What I'm getting back is an empty array. I am using session_start() on each page.
Also, I can set the session successfully from within a single class, but get an empty array back when setting from each class.
// User class
$_SESSION['user'] = array('id' => 1);
$_SESSION['user'] = array('name' => 'Tim Miller');
// Part class
$_SESSION['user'] = array('model' => '12311');
$_SESSION['user'] = array('part' => 'AA34F');
EDIT:
Here is the array I would like to create:
Array (
[user] => Array (
[id] => 1
[name] => Tim Miller
[model] => 12311
[part] => AA34F
[order] => 119026
[serial] => 12001923S3
)
)
Elements 0 and 1 should be set in the user class
Elements 2-3 should be set in the part class
Elements 4-5 should be set in the serial class

Answer 1

You can set it but bit different approach need to be used. You can create an array of sessions with different values.
You have to write session_start() on top of each file where you need to use session.
session_start();
// User class
$_SESSION['user'][] = array('id' => 1);
$_SESSION['user'][] = array('name' => 'Tim Miller');
// Part class
$_SESSION['user'][] = array('model' => '12311');
$_SESSION['user'][] = array('part' => 'AA34F');
print_r( $_SESSION['user'] );
Output looks like:
Array
(
[0] => Array
(
[id] => 1
)
[1] => Array
(
[name] => Tim Miller
)
[2] => Array
(
[model] => 12311
)
[3] => Array
(
[part] => AA34F
)
)
It's upto you how do you want to crate this array.
EDIT:
To get your desire format output and add values to array later in different files you can give a try like:
// Your code here!
session_start();
// User class
$_SESSION['user'][] = array('id' => 1, 'name' => 'Tim Miller');
// Part class
$key = -1
$key = array_search( 1, array_column($_SESSION['user'], 'id') );
// Here 1 in array_search is id of user your can use $id to add data to correct user's by id.
if( $key > -1 ) {
$_SESSION['user'][ $key ] = array_merge( $_SESSION['user'][ $key ], array('model' => '12311', 'part' => 'AA34F') );
}
print_r( $_SESSION['user'] );
This will give you following output:
Array
(
[0] => Array
(
[id] => 1
[name] => Tim Miller
[model] => 12311
[part] => AA34F
)
)