只有数组中的最后一个值被发布到mysql数据库才需要发布所有值

I am currently using codeigniter to grab data from a MySQL table and displaying it on screen. The data is being displayed in an html form so when the user logs into my website the data from the database is already being displayed.

What I would like to happen is if the user changes some of the data in the fields and then pushes the upload button the data should be pushed back to the database and if they refresh the screen their changes should show.

At the moment when I go to push the changes only the last values in the array are being sent. How can I have all of the values in my array sent to the MySQL database. Below is my code for the view, controller, and model. Any help is greatly appreciated!

View

<?php 
    $i=0;
    echo form_open('site/push_data');
            foreach($query as $row): 
                echo form_input('lab['.$i.'][priority]', $row->priority);
                echo form_input('lab['.$i.'][item]', $row->item);
                echo form_input('lab['.$i.'][equipment]', $row->equipment);
                echo form_input('lab['.$i.'][post]', $row->post);
                echo form_input('lab['.$i.'][item_type]', $row->item_type); 
                $i++;
             endforeach;
    echo form_submit('submit', 'Push');
    echo form_close();
?>
<h4><?php echo anchor('login/logout', 'Logout'); ?></h4>

Controller

function push_data()
{
    $this->load->model('display_lab_data');
    $this->display_lab_data->writeToDB($this->input->post('lab'));
}

Model

function writeToDB($data) 
    {
        for($i = 0; $i < 6; $i++)
        {
            print_r($_POST['lab'][$i]);
            $this->db->update_batch('lab_priority_list', $_POST['lab'][$i]);
        }
        /*print_r($_POST['lab']);
        foreach($_POST['lab'] as $Value)
        {
            $this->db->update('lab_priority_list', $Value);
        }*/
    }

Current content of my array

Array ( [priority] => 600 [item] => 78920 [equipment] => machine 53 [post] => blidoolpoop [item_type] => 1 ) Array ( [priority] => 600 [item] => 78920 [equipment] => machine 53 [post] => blidoolpoop [item_type] => 1 ) Array ( [priority] => 600 [item] => 78920 [equipment] => machine 53 [post] => blidoolpoop [item_type] => 1 ) Array ( [priority] => 600 [item] => 78920 [equipment] => machine 53 [post] => blidoolpoop [item_type] => 1 ) Array ( [priority] => 600 [item] => 78920 [equipment] => machine 53 [post] => blidoolpoop [item_type] => 1 ) Array ( [priority] => 600 [item] => 78920 [equipment] => machine 53 [post] => blidoolpoop [item_type] => 1 )