cypher

In Neo4j 2.0 you can create schema indexes for your labels and the properties you use for lookup: CREATE INDEX ON :User(username) CREATE INDEX ON :Role(name) To create relationships you might use: MATCH (u:User {username:’admin’}), (r:Role {name:’ROLE_WEB_USER’}) CREATE (u)-[:HAS_ROLE]->(r) The MATCH will use an index if possible. If there is no index, it will lookup … Read more

So, this gives you all nodes: MATCH (n) RETURN n; If you want to delete everything from a graph, you can do something like this: MATCH (n) OPTIONAL MATCH (n)-[r]-() DELETE n, r; Updated for 2.0+ Edit: Now in 2.3 they have DETACH DELETE, so you can do something like: MATCH (n) DETACH DELETE n;

That’s in the reference docs, see http://docs.neo4j.org/chunked/stable/query-set.html#set-set-a-label-on-a-node, you need to use set to a add a label to a existing node: match (n {id:desired-id}) set n :newLabel return n

You can put this condition in the WHERE clause: MATCH (n) WHERE n:Male OR n:Female RETURN n EDIT As @tbaum points out this performs an AllNodesScan. I wrote the answer when labels were fairly new and expected the query planner to eventually implement it with a NodeByLabelScan for each label, as it does for the … Read more

using regular expressions: http://neo4j.com/docs/developer-manual/current/#query-where-regex start n = node(*) where n.Name =~ ‘.*SUBSTRING.*’ return n.Name, n;

To get all distinct node labels: MATCH (n) RETURN distinct labels(n) To get the node count for each label: MATCH (n) RETURN distinct labels(n), count(*)

Update 01/10/2013: Came across this in the Neo4j 2.0 reference: Try not to use optional relationships. Above all, don’t use them like this: MATCH a-[r?:LOVES]->() WHERE r IS NULL where you just make sure that they don’t exist. Instead do this like so: MATCH a WHERE NOT (a)-[:LOVES]->() Using cypher for checking if relationship doesn’t … Read more