CODEWITHSUNDEEP
javaneo4jneo4j-browser
Ish Montalvo
Ish Montalvo

Reputation: 181

How to search for all nodes and relationships connected to a specific top node in neo4j

I have started using neo4j and I have several versions of a graph in my neo4j database (the only thing that changes is the timestamp at the top node).

I was wondering how to get only the relations to that one node. I currently use this:

"START n=node(*) MATCH (n)-[r]->(m) RETURN n,r,m;"

But this just displays all of them. I know I have to change the n=node(*) but I don't know to what. (the name of the top node is: Info) so maybe something like

"START n=node(i:Info{timeStamp:'20/04/2018'}) MATCH (n)-[r]->(m) RETURN n,r,m;"

but that would just give me the relations to that one node... and I need the whole graph

Upvotes: 1

Views: 130

Answers (1)

cybersam
cybersam

Reputation: 66989

Do this:

MATCH (n:Info)-[r]->(m)
WHERE n.timeStamp = '20/04/2018'
RETURN n, r, m;

For quicker access to the top node, you should also create an index on :Info(timeStamp):

CREATE INDEX ON :Info(timeStamp);

[UPDATED]

To also get all the relationships and nodes to depth 2, you could do this:

MATCH (n:Info)-[r1]->(m1)-[r2]->(m2)
WHERE n.timeStamp = '20/04/2018'
RETURN n, r1, m1, r2, m2;

To get all the relationships and nodes up to an arbitrary depth (say, 5), you can do this (each returned path will be one of the matching paths from n to a child node):

MATCH path=(n:Info)-[r*..5]->(m)
WHERE n.timeStamp = '20/04/2018'
RETURN path;

You could also just use [r*] for an unbounded variable-length search, but that can cause the server to run out of memory or take an extremely long time to finish.

Upvotes: 1

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