How to get formidable entry ID by post ID? [closed]

So, after a lot of searching (which is funny, because it’s such a basic function which should apear in the documents) i found that:

what you have to do to get the current post entry id is:

<?php $entry_id = $wpdb->get_var("SELECT id FROM $frmdb->entries WHERE post_id='". $post->ID ."'"); ?>

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)