function is_comment_owner($comment_id, $user_id) {
    $this->db->where('comment_id', $comment_id);
    $this->db->where('user_id', $user_id);
    $this->db->from('comments_table');
    if ($this->db->count_all_results() > 0) {
        return TRUE;
    } else {
        return FALSE;
    }
}