Update Islandora Compound Objects Relationships

upd_compound_inclusion_relationship_to_book.php

// Requires devel (doesn't need to be enabled).
// Head to https://<host.domain.tld>/devel/php to EXECUTE THIS LIVE. 
// Just want to see the data this will spit out?  Comment out lines 
// starting with "$res" and "$res2" which are the only calls making actual modification.

$pid = 'BC15-14:852'; // This is your compound object's PID. 
$compound = islandora_compound_object_get_parts($pid);

if (empty($compound)) {
  // Not Compound.
  return FALSE;
}

$parent = array_shift($compound);
if (!$parent = islandora_object_load($parent)) {
  // Couldn't load Object.
  return FALSE;
}

if (empty($compound)) {
  // No Children.
  return FALSE;
}

$new_collection = $parent->id;
$old_collection = $parent->getParents();
$old_collection = array_shift($old_collection);
dpm($old_collection, 'old collection');
dpm($new_collection, 'new collection target');

foreach($compound as $child) {
  if (!$child = islandora_object_load($child)) {
    // Couldn't load Object.
    return FALSE;
  }

  dpm($child->getParents(), "{$child->id} before");
  // Remove the old relationship.
  $res = $child->relationships->remove(FEDORA_RELS_EXT_URI, 'isMemberOf', $old_collection);
  // Add the correct relationship.
  $res2 = $child->relationships->add(FEDORA_RELS_EXT_URI, 'isMemberOf', $new_collection);
  dpm($child->getParents(), "{$child->id} after (rem: $res & add: $res2)");
}