I have the following graph, describing co-occurrence of car brands in documents:
CREATE
(`0` :Car {value:"Ford"})
, (`1` :Car {value:"Subaru"})
, (`2` :Car {value:"VW"})
, (`0`)-[:`DOCUMENT` {value:"DOC-1"}]->(`1`)
, (`0`)-[:`DOCUMENT` {value:"DOC-2"}]->(`1`)
, (`1`)-[:`DOCUMENT` {value:"DOC-3"}]->(`2`);
If there are many relationships between two nodes - for the purpose of visualization - I want to replace it with a single one and calculate the weight:
VW ---1--- Subaru ---2--- Ford
How can this be achieved?
I tried the following query:
MATCH (n1)-[r1:DOCUMENT]-(n2)
RETURN n1, n2, apoc.create.vRelationship(n1, 'WEIGHT', {weight:count(r1)}, n2);
but this is not the expected result:
If the relationship direction is not specified in MATCH (n1)-[r1:DOCUMENT]-(n2) RETURN *;
, every relationship is returned twice:
╒══════════════════╤══════════════════╤═════════════════╕
│"n1" │"n2" │"r1" │
╞══════════════════╪══════════════════╪═════════════════╡
│{"value":"Ford"} │{"value":"Subaru"}│{"value":"DOC-1"}│
├──────────────────┼──────────────────┼─────────────────┤
│{"value":"Ford"} │{"value":"Subaru"}│{"value":"DOC-2"}│
├──────────────────┼──────────────────┼─────────────────┤
│{"value":"Subaru"}│{"value":"Ford"} │{"value":"DOC-1"}│
├──────────────────┼──────────────────┼─────────────────┤
│{"value":"Subaru"}│{"value":"Ford"} │{"value":"DOC-2"}│
├──────────────────┼──────────────────┼─────────────────┤
│{"value":"Subaru"}│{"value":"VW"} │{"value":"DOC-3"}│
├──────────────────┼──────────────────┼─────────────────┤
│{"value":"VW"} │{"value":"Subaru"}│{"value":"DOC-3"}│
└──────────────────┴──────────────────┴─────────────────┘
Specify the direction by changing the MATCH
clause to either MATCH (n1)-[r1:DOCUMENT]->(n2)
or MATCH (n1)<-[r1:DOCUMENT]-(n2)
. The remaining part of the query is correct.