Answered Set value on foreign table - relation problems

private function getArtworkCount($gallery_id) {
    $c = $this->modx->newQuery('artworks');
    $c->where(array('gallery_id' => $gallery_id));
    $count = $this->modx->getCount('artworks',$c);
    $this->modx->log(modX::LOG_LEVEL_DEBUG, 'The current value of count:' . $count); // count is zero if this criteria is specified
    return $count;
}