protected function fetchUserId($fieldId)
{
$query = $this->dbHandler->createSelectQuery();
$query->select($this->dbHandler->quoteColumn('contentobject_id'))->from($this->dbHandler->quoteTable('ezcontentobject_attribute'))->where($query->expr->eq($this->dbHandler->quoteColumn('id', 'ezcontentobject_attribute'), $query->bindValue($fieldId)));
$stmt = $query->prepare();
$stmt->execute();
return $stmt->fetchColumn();
}