Change node label in neo4j
MATCH (n:OLD_LABEL {id:14}) REMOVE n:OLD_LABEL SET n:NEW_LABEL Guess this query explains itself.
neo4j
neo4j cypher: how to change the type of a relationship
Unfortunately there is no direct change of rel-type possible at the moment. You can do: MATCH (n:User {name:”foo”})-[r:REL]->(m:User {name:”bar”}) CREATE (n)-[r2:NEWREL]->(m) // copy properties, if necessary SET r2 = r WITH r DELETE r
Why does neo4j warn: “This query builds a cartesian product between disconnected patterns”?
The browser is telling you that: It is handling your query by doing a comparison between every Gene instance and every Chromosome instance. If your DB has G genes and C chromosomes, then the complexity of the query is O(GC). For instance, if we are working with the human genome, there are 46 chromosomes and … Read more
What’s the Cypher script to delete a node by ID?
Assuming you’re referring to Neo4j’s internal node id: MATCH (p:Person) where ID(p)=1 OPTIONAL MATCH (p)-[r]-() //drops p’s relations DELETE r,p If you’re referring to your own property ‘id’ on the node: MATCH (p:Person {id:1}) OPTIONAL MATCH (p)-[r]-() //drops p’s relations DELETE r,p
get all relationships for a node with cypher
The simplest way to get all relationships for a single node is like this: MATCH (:User {username: ‘user6’})-[r]-() RETURN r
A graph DB vs a Prolog (or miniKanren)
No, logic programming as embodied by those things and neo4j are quite different. On one level, you’re right that they conceptually both amount to graph storage and graph query. But for logic programming, it’s only conceptually graph query, there’s no guarantee that it’s actually stored that way (where with neo4j, it is). Second, with logic … Read more
Graph Databases – betting the company on it?
Disclaimer: I work for/with Neo4j Just talking about the maturity here (not technicalities) – Neo Technology as a company with more than 50 employees, $25M funding and a thriving user-base with half a million downloads, 30k new databases running each month and an active community won’t go away. You can also check the SO questions … Read more
Forgot Neo4j Server Password
Depending on environment and installation type you need to look for a file named auth under directory dbms and remove it. In MacOs, for dmg installations (adjust for custom locations): /Users/xyz/Documents/Neo4j/default.graphdb/dbms/auth or (homebrew install) /usr/local/Cellar/neo4j/x.x.x/libexec/data/dbms/auth Windows users should look for same file in the default.graphdb/dbms directory. In Ubuntu /var/lib/neo4j/data/dbms/auth In docker containers /var/lib/neo4j/data/dbms/auth Alternatively, you … Read more
Gremlin remove all Vertex
In more recent terms as of Gremlin 2.3.0, removal of all vertices would be best accomplished with: g.V.remove() UPDATE: For version Gremlin 3.x you would use drop(): gremlin> graph = TinkerFactory.createModern() ==>tinkergraph[vertices:6 edges:6] gremlin> g = graph.traversal() ==>graphtraversalsource[tinkergraph[vertices:6 edges:6], standard] gremlin> g.V().drop().iterate() gremlin> graph ==>tinkergraph[vertices:0 edges:0] Note that drop() does not automatically iterate the Traversal … Read more
How to kill a currently long running query in Neo4j
Available in version >3.1 Enterprise with CALL dbms.listQueries() CALL dbms.killQuery(queryId) Admins may “kill’em all” There is also :queries