Updates the book ID of a page and its children when it moves to a new book.
$book_link: A fully loaded menu link that is part of the book hierarchy.
function book_update_bid($book_link) {
$query = db_select('menu_links');
$query
->addField('menu_links', 'mlid');
for ($i = 1; $i <= MENU_MAX_DEPTH && $book_link["p{$i}"]; $i++) {
$query
->condition("p{$i}", $book_link["p{$i}"]);
}
$mlids = $query
->execute()
->fetchCol();
if ($mlids) {
db_update('book')
->fields(array(
'bid' => $book_link['bid'],
))
->condition('mlid', $mlids, 'IN')
->execute();
}
}