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I have a following Cypher query that returns all Decision that belong to a particular Tag:

MATCH (d:Decision)-[:BELONGS_TO]->(t:Tag) WHERE t.id = {tagId} RETURN d

According to my business logic every Tag can have a set of synonyms:

(t:Tag)<-[:FOR]-(ts:TagSynonym)-[:HAS]->(s:Tag)

and every s:Tag can also have a synonyms associated at the same way.. unlimited depth and where ts.approved = true.

Could you please show how to extend the first query in order to return not only Decisions associated with a start tag (t.id = {tagId}) but also the all Decisions associated with all tag's synonyms(unlimited depth).

Ideally all of these Decisions should be returned under one d variable.

Right now I'm playing with the following query:

MATCH p=(t:Tag)-[:FOR|HAS*]-(end:Tag) 
WHERE t.id = {tagId} AND NOT (end)<-[:FOR]-() 
OPTIONAL MATCH (d:Decision)-[:BELONGS_TO]->(tag) 
RETURN d

but it doesn't work.

UPDATED

I have created a Neo4j sandbox:

http://54.165.53.29:33761/browser/
neo4j
timer-rocks-hilltop

Please use the following query:

MATCH p=(t:Tag)-[:FOR|HAS*0..]-(end:Tag) 
WHERE t.id = 1 AND NOT (end)<-[:FOR]-() 
MATCH (d:Decision)-[:BELONGS_TO]->(end) 
RETURN d

It returns only the last Decision in the path(Decision3) but should also return Decision1 and Decision 2.

This is the sample database username/password: neo4j/neo4j1

I have a 3 Tag and 3 Decision associated with this tag.

Also

Tag 2 is a synonym of Tag 1 and Tag 3 is a synonym of Tag 2.

I need to find all of the Decision by Tag 1 and by its synonyms(Tag 2 and Tag 3). This is decisions: Decision1, Decision2, Decision 3

alexanoid
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1 Answers1

3

There is a subtle thing with variable depth traversals which is the zero depth :

MATCH p=(t:Tag)-[:FOR|HAS*0..]-(end:Tag) 
WHERE t.id = {tagId} AND NOT (end)<-[:FOR]-() 
MATCH (d:Decision)-[:BELONGS_TO]->(end) 
RETURN d

The idea is that, it handles both the cases where t nodes have a FOR or HAS relationships and when they not. The trick is that found tags (even the t node hence the 0) are under the end alias.

You can find a more in depth documentation about variable length relationships in this article : https://graphaware.com/graphaware/2015/05/19/neo4j-cypher-variable-length-relationships-by-example.html

EDIT

It seems the logic for finding the Tag nodes is wrong on your side, the query returns only one Tag due to this part in the query AND NOT (end)<-[:FOR]-(). Remove it and you'll see it returns 3 Decisions

Christophe Willemsen
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  • Thanks for you answer. This query doesn't work as expected and returns only Decision 3 by Tag 1.. but according to my logic result should also contain Decision 1 and Decision 2 – alexanoid Jul 08 '17 at 20:38
  • Right, well please share an online version of your graph then, at least we could test queries. There are plenty of tools, graphgen, sandbox, neo4j console etc. – Christophe Willemsen Jul 08 '17 at 20:44
  • I have provided a snapshot of my database at the question body. Honestly I have no idea how to import this data into sandbox – alexanoid Jul 08 '17 at 20:46
  • I have added sandbox – alexanoid Jul 09 '17 at 07:33