Making shortest path with Apache AGE

Question

I have been reading Jasper Blues' blog post : ROCK ’N’ ROLL TRAFFIC ROUTING, WITH NEO4J but I wanted to port it to AGE. He makes a graph with multiple vertices labeled as Metro and each vertex is connected to another one with an edge labeled as HAS_ROUTE and contains a travelTime property. Here are the vertices and edges created:

CREATE (cavite:Metro {name: 'Cavite Island'})
CREATE (stGermain:Metro {name: 'St Germain'})
CREATE (pigalle:Metro {name: 'Pigalle'})
CREATE (montreal:Metro {name: 'Montreal'})
CREATE (quebec:Metro {name: 'Quebec'})
CREATE (fortTilden:Metro {name: 'Fort Tilden'})
CREATE (intramuros:Metro {name: 'Intramuros'})
CREATE (chinaTown:Metro {name: 'China Town'})
CREATE (stDomingo:Metro {name: 'St Domingo'})
CREATE (coneyIsland:Metro {name: 'Coney Island'})
CREATE (brooklyn:Metro {name: 'Brooklyn'})
CREATE (uptown:Metro {name: 'Uptown'})
CREATE (cardShark:Metro {name: 'Card Shark'})
CREATE (divisoria:Metro {name: 'Divisoria'})
CREATE (ermita:Metro {name: 'Ermita'})
CREATE (nyc:Metro {name: 'NYC'})
CREATE (staIsabel:Metro {name: 'Sta Isabel'})
CREATE (theRuins:Metro {name: 'The Ruins'})
CREATE (phoenix:Metro {name: 'Phoenix'})
CREATE (bastille:Metro {name: 'Bastille'})
CREATE (puertoDelPostigo:Metro {name: 'Puerto del Postigo'})
CREATE (redLight:Metro {name: 'Red Light'})
CREATE (hotelStPaul:Metro {name: 'Hotel St Paul'})
CREATE (cavite)-[:HAS_ROUTE {travelTime: 2.5}]->(intramuros)
CREATE (cavite)-[:HAS_ROUTE {travelTime: 3}]->(fortTilden)
CREATE (stGermain)-[:HAS_ROUTE {travelTime: 9}]->(intramuros)
CREATE (stGermain)-[:HAS_ROUTE {travelTime: 5.6}]->(chinaTown)
CREATE (pigalle)-[:HAS_ROUTE {travelTime: 6}]->(chinaTown)
CREATE (pigalle)-[:HAS_ROUTE {travelTime: 4}]->(montreal)
CREATE (pigalle)-[:HAS_ROUTE {travelTime: 8.5}]->(nyc)
CREATE (montreal)-[:HAS_ROUTE {travelTime: 3}]->(quebec)
CREATE (fortTilden)-[:HAS_ROUTE {travelTime: 13}]->(brooklyn)
CREATE (coneyIsland)-[:HAS_ROUTE {travelTime: 1.5}]->(brooklyn)
CREATE (brooklyn)-[:HAS_ROUTE {travelTime: 2.5}]->(uptown)
CREATE (brooklyn)-[:HAS_ROUTE {travelTime: 5}]->(theRuins)
CREATE (uptown)-[:HAS_ROUTE {travelTime: 5}]->(intramuros)
CREATE (intramuros)-[:HAS_ROUTE {travelTime: 11}]->(chinaTown)
CREATE (intramuros)-[:HAS_ROUTE {travelTime: 16.5}]->(bastille)
CREATE (chinaTown)-[:HAS_ROUTE {travelTime: 7.5}]->(divisoria)
CREATE (chinaTown)-[:HAS_ROUTE {travelTime: 4.5}]->(ermita)
CREATE (chinaTown)-[:HAS_ROUTE {travelTime: 12.5}]->(nyc)
CREATE (theRuins)-[:HAS_ROUTE {travelTime: 4}]->(cardShark)
CREATE (theRuins)-[:HAS_ROUTE {travelTime: 5.5}]->(phoenix)
CREATE (theRuins)-[:HAS_ROUTE {travelTime: 2.5}]->(redLight)
CREATE (cardShark)-[:HAS_ROUTE {travelTime: 4.5}]->(phoenix)
CREATE (divisoria)-[:HAS_ROUTE {travelTime: 6.5}]->(bastille)
CREATE (ermita)-[:HAS_ROUTE {travelTime: 9}]->(puertoDelPostigo)
CREATE (nyc)-[:HAS_ROUTE {travelTime: 10.5}]->(puertoDelPostigo)
CREATE (nyc)-[:HAS_ROUTE {travelTime: 5}]->(stDomingo)
CREATE (nyc)-[:HAS_ROUTE {travelTime: 2}]->(staIsabel)
CREATE (phoenix)-[:HAS_ROUTE {travelTime: 3.5}]->(redLight)
CREATE (phoenix)-[:HAS_ROUTE {travelTime: 10}]->(bastille)
CREATE (bastille)-[:HAS_ROUTE {travelTime: 6.5}]->(hotelStPaul)
CREATE (bastille)-[:HAS_ROUTE {travelTime: 6}]->(puertoDelPostigo)
CREATE (puertoDelPostigo)-[:HAS_ROUTE {travelTime: 3}]->(staIsabel)

Then, in the MOST EXPEDIENT ROUT section, there is this query:

MATCH paths = (a:Metro {name: 'Cavite Island'})-[:HAS_ROUTE*1..6]-(b:Metro {name: 'NYC'})
WITH paths, relationships(paths) AS rels
UNWIND rels AS rel
WITH [metro IN nodes(paths) | metro.name] AS metros,
     collect(rel.travelTime) AS streets,
     sum(rel.travelTime) AS travelTime
  ORDER BY travelTime
RETURN metros, streets, travelTime

But when I run it on AGE, it gives me the following error:

SELECT * from cypher('Saxeburg', $$
        MATCH paths = (a:Metro {name: 'Cavite Island'})-[:HAS_ROUTE*1..6]-(b:Metro {name: 'NYC'})
        WITH paths, relationships(paths) AS rels
        UNWIND rels AS rel
        WITH [metro IN nodes(paths) | metro.name] AS metros, collect(rel.travelTime) AS streets, sum(rel.travelTime) AS travelTime
        ORDER BY travelTime
        RETURN metros, streets, travelTime
$$) as (metros agtype, streets agtype, travelTime agtype);

-- Syntax error at or near "|"
-- Removing the "|" throws another error : Could not find rte for metro

Another method I tried was running the query below, but it throws ERROR: syntax error at or near "|".

SELECT * FROM cypher('demo', $$
    MATCH (from:Metro {name:'Brooklyn'}), (to:Metro {name:'Phoenix'}), path = (from)-[:HAS_ROUTE]->(to)
    RETURN path AS shortestPath,
    reduce(travelTime = 0, r in relationships(path) | travelTime+r.travelTime; 0) AS totalTravelTime
$$) as (totalTravelTime agtype);

How can I properly execute this query so that I can get the shortest path from one vertex to another?

score 1 · Accepted Answer · answered Apr 03 '23 at 03:18

The | symbol is currently not recognized by AGE. You should be able to get a similar result by replacing [metro IN nodes(paths) | metro.name] AS metros with nodes(paths) AS nodes. The only difference is that this will output the entire property of each node instead of only their names.

SELECT * FROM cypher('Saxeburg', $$
    MATCH paths = (a:Metro {name: 'Cavite Island'})-[:HAS_ROUTE*1..6]->(b:Metro {name: 'NYC'})
    WITH paths, relationships(paths) AS rels
    UNWIND rels AS rel
    WITH nodes(paths) AS nodes,
        collect(rel.travelTime) AS streets,
        sum(rel.travelTime) AS travelTime
    RETURN nodes, streets, travelTime
$$) AS (metros agtype, streets agtype, travelTime agtype)
ORDER BY travelTime;

Making shortest path with Apache AGE

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