Codeigniter Datamapper ORM generating wrong query - php

Question

I'm using Datamapper ORM for the first time together with the array and htmlforms extensions for CRUD. So far both extensions worked well for all my models but today I'm facing a weird problem for one model.
When I try to save an object I get this SQL error:
A Database Error Occurred
Error Number: 1054
Unknown Column 'orderitems.orderitem_id' in where clause
SELECT COUNT(*) AS `numrows` FROM (`orderitems`) WHERE `orderitems`.`order_id` = 2 AND `orderitems`.`orderitem_id` NOT IN (8, 9)
Filename: libraries/datamapper.php
Line Number: 2526
I think the correct SQL should be ...AND orderitems.id NOT IN (...) becasue the Orderitem model is referencing itself and not another related model. This error is triggered inside the count() method which is triggered by the save() method which is triggered by the from_array() method of the array DM extension.
Here is my controller code
//Get order
$order = new Order(2);
//Fields to render in the form
$fields = array('orderitem');
//Save changes from $_POST
if($post = $this->input->post())
{
$order->trans_begin();
if ( ! $order->from_array($post, $fields, TRUE) OR $order->trans_status() === FALSE)
$order->trans_rollback();
else
$order->trans_commit();
}
//Load view
$data = array(
'order' => $order,
'fields'=> $fields,
);
$this->load->view('order/edit', $data);
Here is my view code
echo $order->render_form($fields);
And here are the implied models
class Order extends DataMapper {
public $has_one = array('orderstatus', 'place', 'user', 'paymenttype');
public $has_many = array('orderitem');
...
/*SQL:
CREATE TABLE IF NOT EXISTS orders (
id mediumint(4) unsigned NOT NULL auto_increment PRIMARY KEY,
user_id mediumint(1) unsigned, FOREIGN KEY (user_id) REFERENCES users(id) ON UPDATE CASCADE ON DELETE RESTRICT,
orderstatus_id tinyint(1) unsigned, FOREIGN KEY (orderstatus_id) REFERENCES orderstatuses(id) ON UPDATE CASCADE ON DELETE RESTRICT,
place_id tinyint(1) unsigned, FOREIGN KEY (place_id) REFERENCES places(id) ON UPDATE CASCADE ON DELETE SET NULL,
paymenttype_id tinyint(1) unsigned, FOREIGN KEY (paymenttype_id) REFERENCES paymenttypes(id) ON UPDATE CASCADE ON DELETE SET NULL,
total float NOT NULL DEFAULT 0
) ENGINE = InnoDB;
*/
class Orderitem extends DataMapper {
public $has_one = array('order', 'orderitemstatus');
public $has_many = array('orderitemextra');
...
/*SQL:
CREATE TABLE IF NOT EXISTS orderitems (
id int(1) unsigned NOT NULL auto_increment PRIMARY KEY,
order_id mediumint(1) unsigned, FOREIGN KEY (order_id) REFERENCES orders(id) ON UPDATE CASCADE ON DELETE CASCADE,
orderitemstatus_id tinyint(1) unsigned, FOREIGN KEY (orderitemstatus_id) REFERENCES orderitemstatuses(id) ON UPDATE CASCADE ON DELETE RESTRICT,
name varchar(128) NOT NULL,
price float NOT NULL,
) ENGINE = InnoDB;
*/
As I said I had no problems with other models so I don't know if it's a DM problem or a problem with my code or any of my models definitions.
I'll appreciate any kind of help.
Thanks!