Altering Neo4j Cypher Query to Include nodes not connected to graph?

Question

I am using the below code to return all nodes and edges (3 level of depth) from Neo4j and format the response as GraphJSON. I am then using some D3 code to visualize the Graph on my front end.

This works fine for nodes that have at least one relationship or edge. However, I also have some nodes that are not connected to any other nodes. I want to also include these nodes in the response of the query.

Any suggestions how I can modify the code below so that it also picks up floating nodes that are not connected by a relationship to the graph?

OPTIONAL MATCH path = (x:entity)-[*..3 {current:true}]->(:entity)

UNWIND nodes(path) as node
UNWIND rels(path) as rel

WITH collect(distinct node) as nodes,
     collect(distinct rel) as rels
WITH apoc.coll.toSet( [n in nodes WHERE n is not null | { id: id(n),label: labels(n),type:"",metadata: properties(n)  } ]) as nodes, 

apoc.coll.toSet([r in rels WHERE r is not null  | { id: id(r),source: id(startNode(r)),relation: type(r),target: id(endNode(r)), directed: "true"  } ]) as rels

RETURN { graph: { type:"",label: "",directed: "true",nodes: nodes,edges: rels, metadata:{ countNodes: size(nodes),countEdges: size(rels) } } } as graph;

Thanks a lot,

InverseFalcon InverseFalcon · Accepted Answer · 2017-05-21T01:55:17

You can add collections together using the + operator, so after you've collected nodes and rels, MATCH to the floating nodes you want to include, collect them, add the collection to your nodes collection, and finish up your query.

Altering Neo4j Cypher Query to Include nodes not connected to graph?

1 Answers