By the way. Having a mathematical background I think that Neo4j should add support for relationships where the start node and end node are the same. Just wanted to throw this out there to force my colleagues to respond to why it isn't supported (I'm sure there is a better reason than "we didn't have any use cases for it when we originally designed Neo4j", which was the response I got when asking about this around the time I got hired).
sneaking-questions-out-into-the-public-ly yours, Tobias On Wed, Dec 30, 2009 at 12:21 PM, Tobias Ivarsson < [email protected]> wrote: > Neo4j does not allow relationships where the start node and end node are > the same. > > It looks like the batch inserter does not verify this constraint which is > why you run into trouble when traversing the graph instead. > > Cheers, > Tobias > > > On Wed, Dec 30, 2009 at 11:17 AM, Núria Trench <[email protected]>wrote: > >> Hi, >> >> I have created a network with the Batch Inserter component which has >> relationships from a node to itself. So, I am unable to traverse this >> network because it throws an exception when the traverser finds a >> relationship that its tail and head node are equals. The exception is the >> following one: >> >> Exception in thread "main" java.lang.IllegalArgumentException: Start node >> equals end node >> at >> org.neo4j.impl.core.RelationshipImpl.<init>(RelationshipImpl.java:58) >> at >> org.neo4j.impl.core.NodeManager.getMoreRelationships(NodeManager.java:604) >> at >> org.neo4j.impl.core.NodeImpl.getMoreRelationships(NodeImpl.java:332) >> at >> org.neo4j.impl.core.NodeImpl.ensureFullRelationships(NodeImpl.java:320) >> at >> org.neo4j.impl.core.NodeImpl.getAllRelationshipsOfType(NodeImpl.java:129) >> at org.neo4j.impl.core.NodeImpl.getRelationships(NodeImpl.java:199) >> at >> org.neo4j.impl.core.NodeProxy.getRelationships(NodeProxy.java:87) >> at >> >> org.neo4j.impl.traversal.AbstractTraverser.addEndNodesToList(AbstractTraverser.java:256) >> at >> >> org.neo4j.impl.traversal.AbstractTraverser.traverseToNextNode(AbstractTraverser.java:201) >> at >> >> org.neo4j.impl.traversal.AbstractTraverser.hasNext(AbstractTraverser.java:134) >> >> How can I traverse this network without getting an exception? I can't >> change >> the schema. >> Thank your very much in advance, >> >> Núria. >> _______________________________________________ >> Neo mailing list >> [email protected] >> https://lists.neo4j.org/mailman/listinfo/user >> > > > > -- > Tobias Ivarsson <[email protected]> > Hacker, Neo Technology > www.neotechnology.com > Cellphone: +46 706 534857 > -- Tobias Ivarsson <[email protected]> Hacker, Neo Technology www.neotechnology.com Cellphone: +46 706 534857 _______________________________________________ Neo mailing list [email protected] https://lists.neo4j.org/mailman/listinfo/user
