Drupal 7 Module Development

Chapter 6
}
foreach ($artworks as $artwork_id => $artwork) {
field_attach_delete('artwork', $artwork);
}
db_ignore_slave();
}
catch (Exception $e) {
$transaction->rollback();
watchdog_exception('artwork', $e, NULL, WATCHDOG_ERROR);
return FALSE;
}
module_invoke_all('entity_delete', $artwork, 'artwork');
// Clear the page and block and artwork caches.
cache_clear_all();
$this->resetCache();
}
return TRUE;
Once again we use a transaction to ensure that the entire deletion process either
succeeds or fails. We first load the artwork objects that we are about to delete,
as other operations will require them. We then handle our own deletion logic:
Removing the appropriate records from the artwork and artwork_revision tables. We
then call field_attach_delete() to let the Field system remove any field data that
was associated with those artworks, and finally disable the slave server as before.
There's one other task to take care of; we need to flush the cache. By default Drupal
caches most page requests for performance. If we've deleted an artwork, however,
we need to remove that page from the cache. There may be many other pages
affected by that deletion, however, so we simply clear the entire page cache with
cache_clear_all(). It will get rebuilt as needed. We also clear the static cache
of loaded artwork objects that the controller maintains so that if later in this same
request someone tries to load the artwork we just deleted they get an error rather
than a ghost object.
And we're done!
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