Inheritance: extends GraphEntityMetadata
 public function hydrateRelationshipEntity(RelationshipEntityMetadata $reMetadata, array $reMap, NodeEntityMetadata $startNodeMetadata, NodeEntityMetadata $endNodeMetadata, $baseInstance, RelationshipMetadata $relationshipEntity, $pov = null)
 {
     /** @var \GraphAware\Neo4j\Client\Formatter\Type\Relationship $rel */
     $rel = $reMap['rel'];
     $relId = $rel->identity();
     if (null !== ($possibleRE = $this->entityManager->getUnitOfWork()->getRelationshipEntityById($relId))) {
         return $possibleRE;
     }
     $start = $this->hydrateNode($reMap['start'], $startNodeMetadata->getClassName(), true);
     $end = $this->hydrateNode($reMap['end'], $endNodeMetadata->getClassName(), true);
     $reInstance = $reMetadata->newInstance();
     $reMetadata->setId($reInstance, $relId);
     $reMetadata->setStartNodeProperty($reInstance, $start);
     $reMetadata->setEndNodeProperty($reInstance, $end);
     $this->entityManager->getUnitOfWork()->addManagedRelationshipEntity($reInstance, $baseInstance, $relationshipEntity->getPropertyName());
     $reMetadata->setId($reInstance, $relId);
     $otherToSet = $relationshipEntity->getDirection() === 'INCOMING' ? $reMetadata->getStartNodeValue($reInstance) : $reMetadata->getEndNodeValue($reInstance);
     $possiblyMapped = $relationshipEntity->getDirection() === 'INCOMING' ? $reMetadata->getStartNodePropertyName() : $reMetadata->getEndNodePropertyName();
     $otherMetadata = $this->entityManager->getClassMetadataFor(get_class($otherToSet));
     foreach ($otherMetadata->getRelationships() as $relationship) {
         if ($relationship->getDirection() !== $relationshipEntity->getDirection() && $relationship->hasMappedByProperty() && $relationship->getMappedByProperty() === $possiblyMapped) {
             if ($relationship->isCollection()) {
                 if (null !== $this->entityManager->getUnitOfWork()->getEntityById($otherMetadata->getIdValue($otherToSet))) {
                     $relationship->initializeCollection($otherToSet);
                     $relationship->addToCollection($otherToSet, $reInstance);
                 }
             } else {
                 if (null === $relationship->getValue($otherToSet)) {
                     $relationship->setValue($otherToSet, $reInstance);
                 }
             }
         }
     }
     foreach ($rel->values() as $k => $value) {
         if (null !== ($prop = $reMetadata->getPropertyMetadata($k))) {
             $prop->setValue($reInstance, $value);
         }
     }
     //$this->entityManager->getUnitOfWork()->addManagedRelationshipEntity($reInstance, $baseInstance, $relationshipEntity->getPropertyName());
     return $reInstance;
 }
 public function getDeleteQuery($entity)
 {
     $id = $this->classMetadata->getIdValue($entity);
     $query = 'START rel=rel(' . $id . ') DELETE rel';
     return Statement::create($query);
 }