public function deleteWordsWithoutObjects()
    {
        $query = $this->dbHandler->createDeleteQuery();

        $query->deleteFrom($this->dbHandler->quoteTable('ezsearch_word'))
            ->where($query->expr->eq($this->dbHandler->quoteColumn('object_count'), ':c'));

        $stmt = $query->prepare();
        $stmt->execute(['c' => 0]);
    }