Drupal 7 Orphaned Node Reference When Deleting Node

I have 2 nodes:

开发者_C百科

• Project
• Bug

A project has node references to Bugs

When I delete a Bug, those node references remain as orphaned. What is the best way to clean this up?

UPDATE (HERE IS WHAT I DID)

function dc_project_management_node_delete($node)
{
    if ($node->type == 'bug_request')
    {
        $bug_request_nid = $node->nid;
        $milestone_ids = db_query('SELECT entity_id FROM {field_data_field_bugs_requests} WHERE field_bugs_requests_nid = :bug_request_nid', array(':bug_request_nid' => $bug_request_nid))->fetchCol();
        $milestones = entity_load('field_collection_item', $milestone_ids);

        foreach($milestones as $milestone)
        {
            for($k=0;$k<count($milestone->field_bugs_requests['und']);$k++)
            {
                if ($milestone->field_bugs_requests['und'][$k]['nid'] == $bug_request_nid)
                {
                    unset($milestone->field_bugs_requests['und'][$k]);
                }
            }

            entity_save('field_collection_item', $milestone);
        }
    }
}

---

If you want referential integrity of sorts (i.e. related bugs are deleted when a project is deleted) you could just do this:

function mymodule_node_delete($node) {
  if ($node->type == 'project') {
    $bug_nids = array();
    foreach ($node->field_bugs[LANGUAGE_NONE] as $bug) {
      $bug_nids[] = $bug['nid'];
    }

    node_delete_multiple($bug_nids);
  }
}