Neo4j Cypher find all paths exploring sorted relationships

Question

I'm struggling for days to find a way for finding all paths (to a maximum length) between two nodes while controlling the path exploration by Neo4j by sorting the relationships that are going to be explored (by one of their properties).

So to be clear, lets say I want to find K best paths between two nodes until a maximum length M. The query will be like:

match (source{name:"source"}), (target{name:"target"}),
p = (source)-[*..M]->(target)
return p order by length(p) limit K;

So far so good. But lets say the relationships of the path have a property called "priority". What I want is to write a query that tells Neo4j on each step of path exploration which relationships should be explored first.

I know that can be possible when I use the java libraries and an embedded database (By implementing PathExpander interface and giving it as input to the GraphAlgoFactory.allSimplePaths() function in Java). But now I'm trying to find a way doing this in a server mode database access using Bolt or REST api.

Is there any way to do this in the server mode? Or maybe using Java libraries functions while accessing the graph in server mode?

I have checked it, it does'nt do what I want, but thanks anyway! — Gongotar

Michael Hunger Michael Hunger · Accepted Answer · 2016-06-25T16:28:41

use labels and an index to find your two start-nodes
perhaps consider allShortestPaths to make it faster

try this:

match (source{name:"source"}), (target{name:"target"}),
p = (source)-[rels:*..20]->(target)
return p, reduce(prio=0, r IN rels | prio + r.priority) as priority 
order by priority ASC, length(p) 
limit 100;

Neo4j Cypher find all paths exploring sorted relationships

2 Answers