Dynamically return virtual relationship based on matched relationships

[maheshwar_ligad]

I have following graph with nodes and relationship 

Country (IN) -[CONTAIN]-> State(MH)-[CONTAIN]->District-[CONTAIN]->Tahashil-[CONTAIN]->Village<-[LIVES]->[Person]<-[HOME]-address


Country(US) -[CONTAIN]-> State(California)-[CONTAIN]->District-[CONTAIN]->Tahashil-[CONTAIN]->Village<-[LIVES]->[Person]<-[HOME]-address<-[OFFICE]-address

additional relation between [Person]-[MATCHED]->[Person]

I have above graph, if person name match I have to return the graph

Actual data 

country-> state-> district->tahasil->village->Person

Output

country -> state-> Person

OR 

country-> Person

OR

country->State->district->Tahasil->Person

How to achieve this using virtualrelationship? Thanks in advance.

[glilienfield]

If your query results in the path identified as ‘actual data’, you can construct a virtual path for each of the paths identified as ‘output’ using the apoc procedure/functions described in the link below. 

https://neo4j.com/labs/apoc/4.2/virtual/virtual-nodes-rels/#_function_overview

[maheshwar_ligad]

@glilienfield Thanks for the response, but can you give me sample example, I am not able to see the sample example in documentation. That will be helpful.

[glilienfield]

Try these.  I matched the full path then returned the path you wanted with virtual relationships.  Match sure the match meets your data model.  There seems to be a little inconsistency with the Person node and its relationship type and direction to its related node. 

Path 1:

match (country:Country)-[r1:CONTAIN]->(state:State)-[r2:CONTAIN]->(district:District)-[r3:CONTAIN]->(tahashil:Tahashil)-[r4:CONTAIN]->(village:Village)<-[r5:LIVES]-(person:Person)
return 
    country, 
    r1, 
    state, 
    apoc.create.vRelationship(person,'LIVES',{}, state),
    person

Path 2:

match (country:Country)-[r1:CONTAIN]->(state:State)-[r2:CONTAIN]->(district:District)-[r3:CONTAIN]->(tahashil:Tahashil)-[r4:CONTAIN]->(village:Village)<-[r5:LIVES]-(person:Person)
return 
    country, 
    apoc.create.vRelationship(person,'LIVES',{}, country),
    person

Path 3:

match (country:Country)-[r1:CONTAIN]->(state:State)-[r2:CONTAIN]->(district:District)-[r3:CONTAIN]->(tahashil:Tahashil)-[r4:CONTAIN]->(village:Village)<-[r5:LIVES]-(person:Person)
return 
    country, 
    r1,
    state,
    r2,
    district,
    r3,
    tahashil,
    apoc.create.vRelationship(person,'LIVES',{}, tahashil),
    person

[maheshwar_ligad]

@glilienfield This looks good but every time I have to write separate cypher query for each one, is it possible to make it dynamic with one single query to return result.

[glilienfield]

Dynamic based on what? You need get the file path and then create the virtual path. This is done with cypher that needs to be written. 

One thing I could think of is if you passed a list of ordered pairs of integers that specified the node indexes of the start and end nodes that you want a virtual relationships between. You could write code that would substitute each segment with a virtual relationships, then output the remaining nodes, relationships, and virtual relationships.

This would be a little complicated, and I would think that you would have known scenarios that you wanted to implement, so you would only write the code for each scenario ones and use many times.