Neo4j如何为同一关系调用不同的属性

Question

I'm using the new algo to calculate similarities, algo.similarity.jaccard and algo.similarity.overlap with the option WRITE, it means, in the relationship SIMILARITY I create properties sim_jaccard and sim_overlap. The problem comes when I call these two properties, for example :

MATCH (u1:User)-[s:SIMILARITY]-> (u2:User)
WITH coalesce(s.sim_jaccard,0) AS sim_jaccard, coalesce(s.sim_overlap,0)  AS sim_overlap
RETURN sim_jaccard, sim_overlap
LIMIT 25

I get:

sim_jaccard  sim_overlap
0            0.8507462686567164
0            0.9253731343283582 
0            0.8208955223880597
0            0.8955223880597015

I think that happens because properties id are different in the relationship:

SIMILARITY <id>: 3300778 sim_overlap: 1.0
SIMILARITY <id>: 2453827 sim_jaccard: 0.6268656716417911

I would like to have:

SIMILARITY <id>: 3300778 sim_overlap: 1.0,  sim_jaccard: 0.6268656716417911

Any idea to solve that?

Thanks in advance.

Answer 1

If you want to modify your graph so the relationships are combined into 1, then APOC Procedures has some refactor procs to merge relationships together (just use the combine value for the given properties).

If you just want your return to combine the values into a single line, then you can modify your query to sum the values for all rels between the two nodes:

MATCH (u1:User)-[s:SIMILARITY]-(u2:User)
WHERE id(u1) < id(u2)
WITH u1, u2, sum(coalesce(s.sim_jaccard,0)) AS sim_jaccard, sum(coalesce(s.sim_overlap,0))  AS sim_overlap
RETURN sim_jaccard, sim_overlap
LIMIT 25

For the approach where you need to MERGE nodes, you'll want to collect the relationships with respect to the end nodes before calling the procedure:

MATCH (u1:User)-[s:SIMILARITY]-(u2:User)
WHERE id(u1) < id(u2)
WITH u1, u2, collect(s) as rels
CALL apoc.refactor.mergeRelationships(rels, {properties:'combine'}) YIELD rel
RETURN count(rel)

sum(coalesce(s.sim_jaccard,0)) AS sim_jaccard, sum(coalesce(s.sim_overlap,0)) AS sim_overlap RETURN sim_jaccard, sim_overlap LIMIT 25