Neo4j with all relations between all nodes

Question

I'm parsing a cypher query to a .gexf (xml) file. Entering this query in the Neo4j admin gui returns all nodes with their interconnecting relationships (relations between all b-nodes)

START a=node(52681) MATCH(a)-[r]-(b) RETURN a,r,b

The neo4j webgui seems to make it's own queries since it draws up all the relationships between the b-nodes and not just between the a and b-nodes. The JSON response contains no data of which I can parse an xml file with the relationships between the b-nodes.

I've resolved this so far by doing a seperate query for each and every b-node:

MATCH (a)-[r]-(b) WHERE id(a)=52681 AND id(b)=12345

But that doesn't seem like very good design... I would like to get this done in one query only.

Also, I tend to overcomplicate things.

Answer 1

I don't think there's an easy/efficient way to do this.

Consider that the paths between each pair of nodes are likely variable in size, and therefore something like (a)-[r]-(b) will only get you the results you want if a and b are both one degree away.

If they are, however, all only one degree away (and assuming no self-loops, which would be easy enough to take care of anyway), something like

MATCH (a)-[r]-(b) RETURN a, r, b

...would likely do the trick, albeit in a horribly inefficient fashion. But if your paths between a and b are > 1 level deep, it obviously won't work.

In that case, something like this might work, but again be horrible:

MATCH (a)-[r:*]-(b) RETURN a, r, b

...but if the depth of your paths are anything more than a few levels, well...ouch.

When you start asking questions of the graph that span the entire graph and require working/traversing the entirety of it, the kinds of questions you're asking start to blow up a bit.

So, likely, the resolution you came up with is probably the only way to really tackle this.

That said, I'd love to know if anyone else has a different take on this.

HTH, if only a bit.