function update_customer($id){

    $data['success']=0;
    if($_POST){
        $data_customer=array(
            'first_name'=>$_POST['first_name'],
            'last_name'=>$_POST['last_name'],
            'phone'=>$_POST['phone'],
            'email'=>$_POST['email'],
            'website'=>$_POST['website'],
            'business_name'=>$_POST['business_name'],
            'business_add'=>$_POST['business_add'],
            'business_cityState'=>$_POST['business_cityState'],
            'cc_type'=>$_POST['cc_type'],
            'cc_number'=>$_POST['cc_number'],
            'cc_exp'=>$_POST['cc_exp'],
            'cc_cvd'=>$_POST['cc_cvd'],
            'billing_add'=>$_POST['billing_add'],
            'billing_zip'=>$_POST['billing_zip'],
            'package'=>$_POST['package'],
            'assigned_zip_code'=>$_POST['assigned_zip_code'],
            'active'=>1
        );
        $this->customer->update_customer($id,$data);
        $data['success']=1;
    }
    $data['customer']=$this->customer->get_customer($id);

    $this->load->view('header');
    $this->load->view('edit_customer',$data);
    $this->load->view('footer');
}

function update_customer($id, $data){
    $this->where('id', $id);
    $this->db->update('customers', $data);
}

<?php if($success==1){ ?>
        <div class="successAlert">This customer has been updated.</div>
    <? } ?>

    <div class="mainForm">
        <?php echo validation_errors(); ?>

        <form action="<?=base_url()?>customers/update_customer/<?=$customer['id']?>" method="post">

            <label for="first_name">First Name:</label>
            <input type="input" name="first_name" value="" /><br />
            <hr>

$data_customer = $_POST;
$data_customer['active'] = 1;