CIP2026-03-18: Temporal Graph Queries — AS OF Clause

[ADunfield]

Summary

This CIP proposes a FOR VALID_TIME AS OF clause (shorthand: AS OF) for Cypher MATCH patterns, enabling point-in-time queries over relationships annotated with valid time periods.

Motivation

Temporal data — ownership changes, organisational structures, regulatory assignments, contract periods — is ubiquitous in graph modelling. Cypher has no native syntax for querying a graph as it existed at a point in time. Today, developers must write manual IS NULL OR predicates on every relationship hop, producing verbose, error-prone, and optimiser-opaque queries.

A three-hop temporal traversal today requires six predicates. This CIP reduces it to a single AS OF clause.

Proposed syntax

-- Single-hop point-in-time query
MATCH (e:Employee {id: $id})-[r:MANAGED_BY]->(m:Manager) AS OF date('2024-06-15')
RETURN m.name

-- Multi-hop temporal traversal
MATCH (f:Facility)-[:OWNED_BY]->(:Company)-[:SUBJECT_TO]->(:Authority) AS OF $asOf
RETURN *

Full EBNF, semantics, six examples, SQL:2011 alignment, and a Phase 1 parse-time rewrite rule (no storage changes required) are in the CIP document.

Reference implementation

A working implementation demonstrating these semantics as Neo4j procedures and user functions, validated on a production graph with 3.1M+ temporally-annotated relationships:

https://github.com/DIGITAL-FABRIC-AI/neo4j-temporal-graph

Prior art

Aligned with SQL:2011 FOR VALID_TIME AS OF semantics, adapted for Cypher's relationship-centric data model.

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Author: Ashley Dunfield ashley@digital-fabric.com

[hvub]

Hello Ashley,

Thank you very much for this interesting proposal. As you can see on the openCypher website, "with ISO/IEC 39075 GQL, the purpose of openCypher is to pave the road to GQL for openCypher implementers. Changes to openCypher are made by adding GQL features to openCypher."

Unfortunately, your CIP does not propose functionality standardized in GQL at this point.

The route for adding functionality to openCypher is to contribute ISO/IEC 39075 GQL, which you can do by joining your national standards body.

The ISO/IEC JTC1 SC32 WG3, the working group responsible for GQL, has an open Language Opportunity — think of a backlog item — for bi-temporal support. However, there is a significant amount of work required to make the happen, even with the SQL precedence, so that no one has picked it up yet.

Thanks + Best
-Hannes