Greetings,
Apologies if info around this topic exists. I'm using Neo4j Community 3.5.1 w/ apoc-3.5.0.3-all.
Goal
Here is what I am trying to achieve... I want to run a cypher query that outputs a JSON file that is in the format that is consumable/readable by D3.js to display a Sankey Diagram. This site displays the D3 source files. Here is the JSON formatted structure I am hoping apoc can output that D3 requires...
{
"nodes":[
{"node":0,"name":"node0"},
{"node":1,"name":"node1"},
{"node":2,"name":"node2"},
{"node":3,"name":"node3"},
{"node":4,"name":"node4"}
],
"links":[
{"source":0,"target":2,"value":2},
{"source":1,"target":2,"value":2},
{"source":1,"target":3,"value":2},
{"source":0,"target":4,"value":2},
{"source":2,"target":3,"value":2},
{"source":2,"target":4,"value":2},
{"source":3,"target":4,"value":4}
]}
This is what the properly formatted json file in D3 Sankey will look like...
What I'm trying
I've got a working cypher query that returns Source Target Value, but I don't know how to add to the query so that it first groups all of the "nodes" (and numbers the nodes starting at 0) and then groups all of the "links" as seen above.
With "MATCH (bry:Brewery)-[r:BREWS]->(b:Beer)<-[r2:IS_BARREL_AGED]-(ba:BarrelAged)
With bry as brewery, size(collect(b.name)) as number
Where number > 1
Match (brewery)-[:BREWS]->(b2:Beer)<-[:IS_BARREL_AGED]-(ba2:BarrelAged)
With brewery, ba2, count(b2) as cnt
Return brewery.name as source, ba2.name as target, cnt as value Order by target ASC
UNION All
MATCH (bry:Brewery)-[r:BREWS]->(b:Beer)<-[r2:IS_BARREL_AGED]-(ba:BarrelAged)
With bry as brewery, size(collect(b.name)) as number
Where number > 1
Match (brewery)-[:BREWS]->(b2:Beer)<-[:IS_BARREL_AGED]-(ba2:BarrelAged)
Optional Match (brewery)-[:BREWS]->(b2)-[:IS_A]-(bt:BeerType)
With brewery, ba2, count(b2) as cnt, bt
Return ba2.name as source, bt.name as target, cnt as value Order by source ASC"
as query
CALL apoc.export.json.query(query, "/filelocation/barrelsankey.json")
YIELD file, source, format, nodes, relationships, properties, time, rows, batchSize, batches, done, data
RETURN file, source, format, nodes, relationships, properties, time, rows, batchSize, batches, done, data
Does anyone have a suggestion as to what I need to do to my query to make its JSON output the same structure required of D3 Sankey?
Hi Keith,
I'm a SANKEY fan, so I had to take a quick look at this. I'd like to see the answer too! 
My first thought was that there are more than a couple challenges here, and more than a few ways to solve this too. I'd personally sketch out a strategy, break it into pieces then solve each one at at time, finally string it together for a working solution. That still might be best, as I started to pick apart my first thought (virtual nodes/relationships sent to APOC JSON export), I then saw the APOC JSON output
{"nodes(p)":[{"type":"node","id":"0","labels":["....
It looks quite verbose, graph specific and would require post processing in javascript before use, so then I took a look at just generating the JSON directly.
Note, since I don't have your DB I tried to do something generic with one my own DBs that could be run as a starter / demonstration exercise. Just replace the match query clause to find the nodes and relationships you want to send to D3. (and remove the LIMIT 2 of course...)
match p=(a)-[]->(b)
with p limit 2
unwind nodes(p) as n unwind relationships(p) as r
with collect( distinct {node: ID( n), name: n.name}) as nl,
collect( distinct {source: ID(startnode(r)), target: ID(endnode(r)), value: r.score}) as rl
RETURN {nodes: nl, links: rl}
Here is the output
{
"nodes": [
{
"node": 0,
"name": "A"
},
{
"node": 526658,
"name": "B"
},
{
"node": 526657,
"name": "C"
}
],
"links": [
{
"source": 0,
"value": null,
"target": 526658
},
{
"source": 0,
"value": null,
"target": 526657
}
]
}
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