updateItem method

snippet.php

public function updateItem($id, $map, $groups) {
  $this->updateData('inventory', $id, $map); // I update all the columns in the item table 
  $dbo = $this->db->exec('DELETE FROM group_item_mapping WHERE item_id = ' . $id); // here is where I remove the group enrollments. 
  for($i = 0, $l = count($groups); $i < $l; $i++) {
       // here I re-add the enrollments for the selected checkbox options. 
       $this->addData('INSERT INTO group_item_mapping (item_id, group_id) VALUES (:item_id, :group_id)', array( ':item_id' => $id, ':group_id' => $groups[$i] )); 
  }
}