Match Command in Neo4j | 易学教程

问题

I have two graphs with some nodes with similar labels. If I want to fetch part of a graph using match command,then do I need to specify the graph name. For eg., MATCH (dom)<-[:headedby]-(Hd) RETURN count (Hd.name);

I have (dom)<-[:headedby]-(Hd) relation in both the graphs, so which data does it fetch? I'm finding that it is giving me the aggregate count of both the graphs. Please let me know if I have to pass the graph alias also with the match command and how to do it.

Thanks in advance.

This is the import query to the complete model:

LOAD CSV FROM "file:D:\\Neo4j\\demo2dbcopy.csv" AS emp 
MERGE (cname:Cmpname {name: emp[0]}) 
MERGE (clusters:ClustName { name: emp [1]}) 
MERGE (dom:domains { name: emp [2]}) 
MERGE (Hd:Head { name: emp [3]}) 
MERGE (DelHd:DeliveryHead { name: emp [4]}) 
MERGE (Mgr:Managers { name: emp [5]}) 
MERGE (Emp:Employees { name: emp [6]}) 
CREATE (cname)-[:has]->(clusters),
       (clusters)-[:contains]->(dom)<-[:headedby]-(Hd),
      (Hd)-‌[:equals]->(DelHd),
      (DelHd)-[:assistedby]->(Mgr),
      (Mgr)-[:Dividesinto]->(Emp) 
return cname,clusters,dom,Hd,DelHd,Mgr,Emp;

回答1:

If I understand this one correctly want to have multiple subgraphs in one Neo4j database.

I think your model is missing a root node for your subgraphs.

Combine your CSV files to one and add 1 column to separate the different subgraphs. Then the import statement whould look like this:

LOAD CSV FROM "file:D:\\Neo4j\\demo2dbcopy.csv" AS emp
MERGE (root:SubGraph {source: emp[7]})
MERGE (cname:Cmpname {name: emp[0]}) 
MERGE (clusters:ClustName { name: emp [1]}) 
MERGE (dom:domains { name: emp [2]}) 
MERGE (Hd:Head { name: emp [3]}) 
MERGE (DelHd:DeliveryHead { name: emp [4]}) 
MERGE (Mgr:Managers { name: emp [5]}) 
MERGE (Emp:Employees { name: emp [6]}) 
CREATE (root)<-[:PART_OF_SUB_GRAPH]-(cname)-[:has]->(clusters),
       (clusters)-[:contains]->(dom)<-[:headedby]-(Hd),
      (Hd)-‌[:equals]->(DelHd),
      (DelHd)-[:assistedby]->(Mgr),
      (Mgr)-[:Dividesinto]->(Emp) 
return root,cname,clusters,dom,Hd,DelHd,Mgr,Emp;

You probably want to do something like this:

Find all domains from the sub graph "csv1" and return the count of Heads

MATCH (root:SubGraph {source: "csv1"})<--(:Cmpname)-->(:ClustName)-->(dom:domains {name:"foo"})<-[:headedby]-(hd) RETURN dom.name, count (hd.name);

UPDATE: combining the answers of this question en this one here: Differentiating Neo4j queries for different data files

回答2:

I have used the following query in response to above syntax but it is returning me 0 rows where the correct answer must be 7 rows.

MATCH (root:SubGraph {source: "demo2db"})<--(clusters:ClustName{name:"ABC"})-[:contains]->(dom:domains {name:"XYZ"}) RETURN count(dom.name);

来源：https://stackoverflow.com/questions/24751634/match-command-in-neo4j

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neo4j