cypher

问题 My code is below, As per the documentation it should have given me the node values but it is throwing me exception Exception in thread "main" java.lang.ClassCastException: scala.collection.convert.Wrappers$SeqWrapper cannot be cast to org.neo4j.graphdb.Node at com.neo4j.performance.FetchData.main(FetchData.java:32) I'm using Neo4j 2.2.2. import org.neo4j.graphdb.Node; import org.neo4j.graphdb.Result; import org.neo4j.graphdb.Transaction; import java.util.Iterator; import org.neo4j.helpers

问题 Consider I have a bunch of connected nodes in Neo4J, forming a tree or a graph or whatever, and I want to have them in the programming language that I'm using (I'm using Java but that's not important). I know I can have them all with a single cypher query like this: MATCH (n0:Root)-[:Child*0..]->(nx:Node) WHERE ID(n0) = 1 RETURN nx; But the problem I have here is that once returned to Java, I don't know which node is connected to which! How can I return the data so I can reconstruct the graph

问题 MATCH (p:Product), (s:Student), (b:Boy), (a:Attribute) RETURN count(distinct(p)), count(distinct(s)), count(distinct(b)), count(distinct(a)) I want to know how many counts of each node types in the graph using this query. However, the Neo4j Browser gives a warning saying that this query produces a cartesian product. Is there a better way to write the query? 回答1: To get a variety of statistics for your DB, including a count of the number of nodes for every label, you can use the APOC function

问题 I am currently using a neo4j database with 50000 nodes and 2 million relationships to perform cypher MATCH queries, like the one below: start startnode = node(42660), endnode = node(30561) match startnode-[r*1..3]->endnode return r; This query by itself provides 443 rows, but I only want Cypher to find 5 matches and return those only. Allow me to clarify: I do not just want Cypher to return only 5 results, I also want cypher to STOP querying once it finds 5 results. I DO NOT want Cypher to

问题 I have a dense node problem and to get around this I've been using indexing to perform some matching using the native Java API, but I've been giving Cypher a second look and wanted to know if this could be done. Currently my pattern looks like this in Java Code: Node startNode = db.getNodeById(1); Index<Relationship> relationshipIndex = db.index.forRelationships("relationships"); for(Relationship relationship1 : startNode.getRelationships(Direction.OUT)) { Node otherNode = relationship

问题 I have friend-friend data model which has two relationships between any two friend nodes based on how one friend defines the other friend. For example, User "A" can define user "B" as 'FRIEND' and "B" can define "A" as 'BUDDY'. The problems is, when I try to get the 3rd degree of relationship of user "A", it returns user "B", where as the actual result should be "D" only. MATCH(a:Users {first_name : "A"}) -[:BUDDY|FRIEND*3] -> (b) RETURN a,b OR MATCH (a)-[]-(b)-[]-(c)-[]-(d) WHERE a.first

问题 I have some nodes and relation like A -> B ->C -> D ; and B->D So the B C D is a loop, now I want get all relations and each relation distance from node A; I expect result like: {startNode: A, endNode: B, rel:FRIEND, distanceFromAtoEndnode: 1}, {startNode: B, endNode: C, rel:FRIEND, distanceFromAtoEndnode: 2}, {startNode: C, endNode: D, rel:FRIEND, distanceFromAtoEndnode: 3}, {startNode: B, endNode: D, rel:FRIEND, distanceFromAtoEndnode: 2} and my cypher: match p=(n:Person {name:"A"})-[r*1..9

问题 I'm trying to transfert all ingoing and outgoing relationships (including their properties) from a node to another, before deleting the first one. they both have the same label. The discussion started here : Neo4j Cypher : transfer all relationships before replacing a node by another node_query = Neo4j::Session.query.match(old_node: {uuid: node1.uuid}).match(new_node: {uuid: node2.uuid}) types = node_query.match('node-[rel]-()').pluck('DISTINCT type(rel)') types.each do |type| node_query

问题 I am running Neo4J on Docker within Vagrant. I am attempting to LOAD CSV WITH HEADERS from a file within the /import/ directory (I had to move my file there) via a cURL request. My request looks something like this: "LOAD CSV WITH HEADERS FROM \"file:///insert-neo4j.csv\" AS row ... This provides me with the following error: {"results":[],"errors [{"code":"Neo.ClientError.Statement.ExternalResourceFailed","message":"Couldn't load the external resource at: file:/var/lib/neo4j/import/insert

问题 Suppose that i have a graph in which for each pair of nodes m,n of type BallT there can be a node k of type BallD that connects them through relationships of type Rel, that is, there can be multiple patterns of the kind p=(m:BallT)-[r:Rel]-(k:BallD)-[s:Rel]-(n:BallT) . For a given node m (satisfying for example m.key="whatever" ) let's call Nmn the number of BallD connecting m and some node n and N the total number of BallD nodes. For this given node m how can i found all nodes n such that