function delete()
{
//filter used in general
$filter = new field_filter('categoryid', $this->id);
//delete fields that belong to this category
field::delete_records($filter, $this->_db);
//delete the record associating the category to a context level
field_category_contextlevel::delete_records($filter, $this->_db);
//delete the actual category record
parent::delete();
}
