Cypher syntax suggestion: Relationship pattern predicates

Neo4j Graph Platform Cypher
1

Since Neo4j 4.4, there is a new Cypher syntax Node pattern predicates.

Is it possible to implement similar Relationship pattern predicates as well? It would allow querying for a variable-length path pattern for relationships that have properties designating its validity start/end.

Current query to return friends at a specified date:

MATCH p=(n:Person WHERE id(n) = $id)-[:FRIEND_OF*1..5]-(:Person) WHERE all(r IN relationships(p) WHERE r.dateFrom <= $date AND r.dateTo >= $date) RETURN p

Proposed query:

MATCH p=(n:Person WHERE id(n) = $id)-[r:FRIEND_OF*1..5 WHERE r.dateFrom <= $date AND r.dateTo >= $date]-(:Person) RETURN p

The current query searches for all paths first, which is harmful for performance because it can return lots of paths, and post-filters the result.

The proposed query would apply the condition during the traversal, so that only the matching paths are returned.

2

@zakjan

This suggestion is interesting,
but I think would be better to create an issue on GitHub page , using the Feature request template ,
otherwise here this hint could be lost forever :D

3

There is a new syntax in Neo4j, but unfortunately it doesn't work with variable-length relationship paths. WHERE - Cypher Manual

Relationship pattern predicates are not supported for variable-length relationships.