public function removeFileReference($fieldId, $versionNo)
{
$connection = $this->getConnection();
$deleteQuery = $connection->createDeleteQuery();
$deleteQuery->deleteFrom($connection->quoteTable($this->getStorageTable()))->where($deleteQuery->expr->lAnd($deleteQuery->expr->eq($connection->quoteColumn('contentobject_attribute_id'), $deleteQuery->bindValue($fieldId, null, \PDO::PARAM_INT)), $deleteQuery->expr->eq($connection->quoteColumn('version'), $deleteQuery->bindValue($versionNo, null, \PDO::PARAM_INT))));
$deleteQuery->prepare()->execute();
}