Neo4j does not support relationships with the same head and tail AT ALL at the moment. It is an error for a store with the current version to contain such a relationship and any time you try to access such a relationship it will result in an exception. The only solution is to not create such relationships. Normal operation does not allow you to create such relationships, but the batch insertion mode omits a number of these checks.
Cheers, Tobias On Wed, Dec 30, 2009 at 12:34 PM, Núria Trench <[email protected]>wrote: > Ok, thank you for your response. Is there any way to run the traverser > omitting this kind of nodes? > As you have said, there are some algorithms which need to have edges with > the same tail and head node. > > 2009/12/30 Tobias Ivarsson <[email protected]> > > > 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 > > > _______________________________________________ > 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 _______________________________________________ Neo mailing list [email protected] https://lists.neo4j.org/mailman/listinfo/user
