public function beforeDelete()
{
$pks = [];
foreach ($this->owner->tags as $tag) {
$pks[] = $tag->primaryKey;
}
if (count($pks)) {
Tag::updateAllCounters(['frequency' => -1], ['in', 'id', $pks]);
}
Tag::deleteAll(['frequency' => 0]);
TagAssign::deleteAll(['class' => get_class($this->owner), 'item_id' => $this->owner->primaryKey]);
}