Understanding the passing of data/life of a script in web development/CodeIgniter
<?php

class Site extends CI_Controller {

var $task1;
var $tasks = array(
                        "task1" => NULL,
                        "date1" => 0,
                        "date2" => 0,
                        "diff" => 0);

function __construct()
{
    parent::__construct();
    include 'timetask.php';
    $this->task1 = new TimeTask("create");
}

function index()
{
    $this->tasks['task1'] = $this->task1->getTask();
    $this->tasks['diff'] = $this->task1->getTimeDiff();

    if($this->tasks['diff'] == NULL)
    {
            $this->tasks['diff'] = 0;
    }

    $this->load->view('usability_test', $this->tasks);
}

function origIndex()
{
    $this->task1->setDate1(new DateTime());
    $this->tasks['date1'] = $this->task1->getDate1()->getTimestamp();
    $data = array();

    if($q = $this->site_model->get_records())
    {
        $data['records'] = $q;
    }

    $this->load->view('options_view', $data);
}

function create()
{
    $this->task1->setDate2(new DateTime());
    $this->tasks['date2'] = $this->task1->getDate2()->getTimestamp();

    $data = array(
            'author' => $this->input->post('author'),
            'title' => $this->input->post('title'),
            'contents' => $this->input->post('contents')
    );

    $this->site_model->add_record($data);
    $this->index();

}

<?php

class TimeTask
{
private $task;

/**
 * @var DateTime
 */
private $date1, $date2;

function __construct($currTask)
{
    $this->task = $currTask;
}

public function getTimeDiff()
{
    $hasDiff = $this->date1 && $this->date2;
    if ($hasDiff) {
        return $this->date2->getTimestamp() - $this->date1->getTimestamp();
    } else {
        return NULL;
    }
}

public function __toString()
{
    return (string) $this->getTimeDiff();
}

/**
 * @return DateTime
 */
public function getDate1()
{
    return $this->date1;
}

/**
 * @param DateTime $date1
 */
public function setDate1(DateTime $date1)
{
    $this->date1 = $date1;
}

/**
 * @return DateTime
 */
public function getDate2()
{
    return $this->date2;
}

/**
 * @param DateTime $date2
 */
public function setDate2(DateTime $date2)
{
    $this->date2 = $date2;
}

/**
 * @return get current task
 */
 public function getTask()
 {
        return $this->task;
 }

}

?>

<?php echo form_open('site/create');?>
...and...
<?php echo anchor("site/delete/$row->id", $row->title); ?>

CREATE TABLE IF NOT EXISTS  `ci_sessions` (
session_id varchar(40) DEFAULT '0' NOT NULL,
ip_address varchar(45) DEFAULT '0' NOT NULL,
user_agent varchar(120) NOT NULL,
last_activity int(10) unsigned DEFAULT 0 NOT NULL,
user_data text NOT NULL,
PRIMARY KEY (session_id),
KEY `last_activity_idx` (`last_activity`)

$config['sess_use_database'] = TRUE;
$config['sess_table_name'] = 'ci_sessions';