LeanMapper\Row::setReferencedRow PHP Method

    public function setReferencedRow(self $row = null, $viaColumn)
    {
        $this->referencedRows[$viaColumn] = $row;
    }

 /**
  * @param Entity|null $entity
  * @param Property|string $property micro-optimalization
  * @throws InvalidMethodCallException
  */
 protected function assignEntityToProperty(Entity $entity = null, $property)
 {
     if ($entity !== null) {
         $this->useMapper($entity->mapper);
         $this->setEntityFactory($entity->entityFactory);
         $table = $this->mapper->getTable(get_class($entity));
         $idProperty = $this->mapper->getEntityField($table, $this->mapper->getPrimaryKey($table));
     }
     if (is_string($property)) {
         $property = $this->getCurrentReflection()->getEntityProperty($property);
     }
     $relationship = $property->getRelationship();
     if (!$relationship instanceof Relationship\HasOne) {
         throw new InvalidMethodCallException("Cannot assign value to property '{$property->getName()}' in entity " . get_called_class() . '. Only properties with m:hasOne relationship can be set via magic __set.');
     }
     $column = $relationship->getColumnReferencingTargetTable();
     if ($entity !== null) {
         $this->row->setReferencedRow($entity->row, $column);
         $this->row->{$column} = $entity->{$idProperty};
     } else {
         $this->row->{$column} = null;
     }
 }