exclude relations based on relation parameters

1
votes

I've got a neo4j cypher traversal problem.

setup: I have a query which starts at node "a" and gives me all the paths with the relation "FOO". All these "FOO" relations have a parameter "BAR". The parameter "BAR" can have 2 (or more) values "1" and "2". Now I want to exclude all paths containing one or more FOO.BAR="2" relation.

The query: START a=node(x) MATCH a-[rh:FOO*]->b RETURN rh; rh gives me all possible paths, but I don't know how to add criteria regarding a relationship.

I have a scenario created in the console (http://console.neo4j.org/?id=219eub)


    create 
    (a  {name:"A"}),
    (b {name:"B"}),
    (c  {name:"C"}),
    (d  {name:"D"}),
    b-[:FOO{BAR:'1'}]->a,
    d-[:FOO{BAR:'1'}]->a,
    c-[:FOO{BAR:'2'}]->b,
    d-[:FOO{BAR:'1'}]->c

    START n=node(4) 
    MATCH n-[rh:FOO*]-b 
    RETURN rh;

This gives me Query Results


    +---------------------------------------------------------------------------+
    | n.name | rh                                                      | b.name |
    +---------------------------------------------------------------------------+
    | "D"    | [:FOO[2] {BAR:"1"}]                                     | "A"    |
    | "D"    | [:FOO[3] {BAR:"1"}]                                     | "C"    |
    | "D"    | [:FOO[3] {BAR:"1"},:FOO[1] {BAR:"2"}]                   | "B"    |
    | "D"    | [:FOO[3] {BAR:"1"},:FOO[1] {BAR:"2"},:FOO[0] {BAR:"1"}] | "A"    |
    +---------------------------------------------------------------------------+

but I only want


    +---------------------------------------------------------------------------+
    | n.name | rh                                                      | b.name |
    +---------------------------------------------------------------------------+
    | "D"    | [:FOO[2] {BAR:"1"}]                                     | "A"    |
    | "D"    | [:FOO[3] {BAR:"1"}]                                     | "C"    |
    +---------------------------------------------------------------------------+
1
neo4jcypher

1 Answers

1
votes

Since rh is a collection you can apply predicate functions:

START n=node(4) 
MATCH n-[rh:FOO*]->b 
WHERE not any(r in rh where r.BAR="2") 
RETURN rh;