Looping through relatiomships manually is the way to go. However there's a new component in https://svn.neo4j.org/laboratory/components/lucene-index/ which can index relationships and do fast lookups on whether or not a relationship (with a certain attribute even) exists between two nodes.
You'll need to go with the latest kernel then as well (as seen in https://svn.neo4j.org/laboratory/components/lucene-index/pom.xml). 2010/7/30, Arijit Mukherjee <ariji...@gmail.com>: > Hi All > > I have a requirement where I must check if there is an already > existing relationship between two nodes (say N1 and N2). Right now, > I'm doing it as follows: > > boolean found = false; > final Iterable<Relationship> currentRels = > N1.getRelationships(RelTypes.KNOWS, Direction.OUTGOING); > for (Relationship rel : currentRels) { > found = rel.getEndNode().equals(N2); > if (found) { > do something - like add some property to the existing relationship; > break; > } > } > if (!found) { > create new relationship between N1 and N2; > } > > This means, for a high volume of data, all the relations going out of > N1 will be retrieved and checked - and this seems costly. I'm using > the 1.0 API, and wasn't able to find anything that would directly > check whether N1 has an outgoing relationship with N2 - like > N1.hasRelationship(N2, Direction.OUTGOING) - or something similar. I > think there was a similar mail sometime ago. Has there been any > updates lately which allows such checks? Or, is there any other direct > way to do this with the 1.0 API? > > Regards > Arijit > > -- > "And when the night is cloudy, > There is still a light that shines on me, > Shine on until tomorrow, let it be." > _______________________________________________ > Neo4j mailing list > User@lists.neo4j.org > https://lists.neo4j.org/mailman/listinfo/user > -- Mattias Persson, [matt...@neotechnology.com] Hacker, Neo Technology www.neotechnology.com _______________________________________________ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
