Neos\Neos\TYPO3CR\Transformations\AssetTransformation::execute PHP Method

    public function execute(NodeData $node)
    {
        foreach ($node->getNodeType()->getProperties() as $propertyName => $propertyConfiguration) {
            if (isset($propertyConfiguration['type']) && in_array(trim($propertyConfiguration['type']), $this->getHandledObjectTypes())) {
                if (!isset($nodeProperties)) {
                    $nodeRecordQuery = $this->entityManager->getConnection()->prepare('SELECT properties FROM typo3_typo3cr_domain_model_nodedata WHERE persistence_object_identifier=?');
                    $nodeRecordQuery->execute([$this->persistenceManager->getIdentifierByObject($node)]);
                    $nodeRecord = $nodeRecordQuery->fetch(\PDO::FETCH_ASSOC);
                    $nodeProperties = unserialize($nodeRecord['properties']);
                }
                if (!isset($nodeProperties[$propertyName]) || !is_object($nodeProperties[$propertyName])) {
                    continue;
                }
                /** @var Asset $assetObject */
                $assetObject = $nodeProperties[$propertyName];
                $nodeProperties[$propertyName] = null;
                $stream = $assetObject->getResource()->getStream();
                if ($stream === false) {
                    continue;
                }
                fclose($stream);
                $objectType = TypeHandling::getTypeForValue($assetObject);
                $objectIdentifier = ObjectAccess::getProperty($assetObject, 'Persistence_Object_Identifier', true);
                $nodeProperties[$propertyName] = array('__flow_object_type' => $objectType, '__identifier' => $objectIdentifier);
            }
        }
        if (isset($nodeProperties)) {
            $nodeUpdateQuery = $this->entityManager->getConnection()->prepare('UPDATE typo3_typo3cr_domain_model_nodedata SET properties=? WHERE persistence_object_identifier=?');
            $nodeUpdateQuery->execute([serialize($nodeProperties), $this->persistenceManager->getIdentifierByObject($node)]);
        }
    }