Cypher queries in py2neo

Question

I am starting to use py2neo and tried to work on some sample data sets. Here is (simplified) original set of queries:

CREATE (Ann:person{name:'Ann',gender:'female'})
CREATE (Target:store{name:'Target',location:'New York'})
CREATE (Ann)-[:PURCHASED {amount:'100',status:'denied'}]->(Target)

In py2neo I tried this:

ann,=graph_db.create(node({name:'Ann',gender:'female'}))
ann.add_labels("person")

target,=graph_db.create(node({name:'Target',location:'New York'}))
target.add_labels("merchant")

(ann,"PURCHASED",target,{'amount':'100', 'status':'denied'})

This query returns

(Node('http://localhost:7474/db/data/node/0'),
 'PURCHASED',
 Node('http://localhost:7474/db/data/node/3'),
 {'amount': '100', 'status': 'denied'})

I have a lot of different users, so I wanted to find all of them whose transactions were denied

query_string="""
MATCH (customer:person)-[r:PURCHASED]->(merchant)
WHERE r.status = "denied"
RETURN customer.name as customer_name
"""

Then I try to execute it

result = neo4j.CypherQuery(graph_db, query_string).execute()

It returns an empty object. What am I doing wrong?

There's nothing that jumps out as wrong with your query. Have you tried running the same in the browser? — Nigel Small, Oct 18 '14 at 18:12
it turns out that I forgot to put rel when creating a relationship. — Anastasia, Oct 23 '14 at 18:42

score 0 · Answer 1 · edited Oct 31 '15 at 01:20

0

I suggest, when creating a node or a relationship, to use merge_one and create_unique respectively in order to ensure you won't create any duplicates.

E.g:

x=graph.merge_one("Boy","Name",bname)

y=graph.merge_one("Girl","Name",gname)

likes=Relationship(x, "LIKES", y)

graph.create_unique(likes)

edited Oct 31 '15 at 01:20

Pang

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answered Aug 04 '15 at 07:44

panomi

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Cypher queries in py2neo

1 Answers1