ocg 0.2.9

99%+ openCypher-compliant in-memory graph database — 4 backends, 31 algorithms, pure Rust

OCG — OpenCypher Graph

High-performance in-memory graph database with 99%+ OpenCypher compliance, 4 backends, and 31 algorithms — pure Rust.

Overview

OCG executes OpenCypher queries against in-memory property graphs. It is built in pure Rust and exposed to Python via PyO3 bindings.

• 99%+ OpenCypher TCK: 3,859 / 3,897 scenarios passing
• 4 graph backends: PropertyGraph, NetworKitRust, RustworkxCore, Graphrs
• 31 graph algorithms: centrality, community detection, pathfinding, spanning trees, flow, coloring, matching
• Bulk Loader API: 57x faster batch construction vs OpenCypher CREATE statements
• Serialization: save/load graphs to JSON with full metadata
• Python 3.8–3.13, macOS · Linux · Windows

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Installation

pip install ocg

Rust:

[dependencies]
ocg = "0.2"

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Quick Start

Python

from ocg import Graph

graph = Graph()

# OpenCypher queries
graph.execute("CREATE (a:Person {name: 'Alice', age: 30})")
graph.execute("CREATE (b:Person {name: 'Bob', age: 25})")
graph.execute("MATCH (a:Person), (b:Person) WHERE a.name='Alice' AND b.name='Bob' CREATE (a)-[:KNOWS]->(b)")

result = graph.execute("MATCH (a:Person)-[:KNOWS]->(b:Person) RETURN a.name AS from, b.name AS to")
print(result)  # [{'from': 'Alice', 'to': 'Bob'}]

Bulk Loader (10–57x faster)

Bypasses the OpenCypher parser for large batch operations:

from ocg import Graph

graph = Graph()

node_ids = graph.bulk_create_nodes([
    (["Person"], {"name": "Alice", "age": 30}),
    (["Person"], {"name": "Bob",   "age": 25}),
])

graph.bulk_create_relationships([
    (node_ids[0], node_ids[1], "KNOWS", {"since": 2020}),
])

result = graph.execute("MATCH (a)-[:KNOWS]->(b) RETURN a.name, b.name")

Serialization

graph.save("my_graph.json")
loaded = Graph.load("my_graph.json")

Rust

use ocg::{PropertyGraph, execute};

let mut graph = PropertyGraph::new();
execute(&mut graph, "CREATE (a:Person {name: 'Alice'})").unwrap();
let result = execute(&mut graph, "MATCH (n:Person) RETURN n.name").unwrap();

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Graph Backends

Backend	Class	Description
PropertyGraph	Graph	Native petgraph-based property graph
NetworKitRust	NetworKitGraph	Port of NetworKit algorithms to pure Rust
RustworkxCore	RustworkxGraph	IBM Qiskit rustworkx-core algorithms
Graphrs	GraphrsGraph	graphrs-based community detection

All four backends expose identical APIs: OpenCypher execution, bulk loader, 31 algorithms, and save/load.

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Graph Algorithms (31)

All algorithms are available on all 4 backends.

Category	Algorithms
Centrality	degree, betweenness, closeness, pagerank
Pathfinding	bfs, dijkstra, astar, bellman_ford, floyd_warshall, all_pairs
Spanning Trees	minimum, maximum
DAG	topological_sort, is_dag, find_cycles, dag_longest_path, dag_longest_path_weighted, transitive_closure
Flow	max_flow, min_cut_capacity
Coloring	node_coloring, edge_coloring, chromatic_number
Matching	max_weight_matching, max_cardinality_matching
Community	louvain, label_propagation, girvan_newman
Components	connected_components, strongly_connected_components

from ocg import Graph

graph = Graph()
# ... populate graph ...

scores = graph.pagerank(damping=0.85, max_iter=100)
communities = graph.louvain()
path = graph.dijkstra(source_id, target_id)

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Supported OpenCypher Features

Clauses

• MATCH, OPTIONAL MATCH, variable-length paths [*1..3]
• CREATE, MERGE, SET, DELETE, DETACH DELETE, REMOVE
• WITH, UNWIND, RETURN, WHERE
• ORDER BY, SKIP, LIMIT, DISTINCT
• UNION, UNION ALL

Expressions

• Property access, list indexing, string slicing
• Arithmetic: +, -, *, /, %, ^
• Comparison: =, <>, <, >, <=, >=
• Logical: AND, OR, NOT, XOR
• String: STARTS WITH, ENDS WITH, CONTAINS, =~
• Null: IS NULL, IS NOT NULL
• List: IN, comprehensions, quantifiers

Functions (60+)

• String: substring, trim, toLower, toUpper, split, replace
• Math: abs, ceil, floor, round, sqrt, sin, cos, log
• List: size, head, tail, range, reverse, keys
• Aggregation: count, sum, avg, min, max, collect
• Temporal: date, datetime, localDatetime, duration
• Predicates: exists, all, any, none, single

Procedures

• db.labels(), db.relationshipTypes(), db.propertyKeys()
• dbms.components()

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TCK Compliance

3,859 / 3,897 scenarios passing — 99.0%

Validated against the openCypher Technology Compatibility Kit. 23 scenarios skipped (TCK infrastructure), 15 scenarios pending (edge cases in arithmetic and aggregation).

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Development

# Build
cargo build --release

# Unit tests
cargo test --no-default-features

# OpenCypher TCK
cargo test --test tck_property_graph --no-default-features

# Python wheel (requires maturin)
maturin develop --features python

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Credits

• petgraph — core graph data structures (MIT/Apache-2.0)
• rustworkx-core — graph algorithms (Apache-2.0)
• graphrs — community detection (MIT)
• openCypher TCK — test compatibility kit (Apache-2.0)
• Algorithm designs inspired by NetworKit (MIT)

Algorithm implementations (PageRank, Betweenness Centrality, Dijkstra, etc.) are based on published academic work. See NOTICE file for complete citations.

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License

Apache-2.0 — see LICENSE and NOTICE files.

OpenCypher® and Cypher® are registered trademarks of Neo4j, Inc. This project implements the open OpenCypher specification and is not affiliated with Neo4j.

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Contributing

Issues and proposals may be submitted via GitHub. Contributions are evaluated on a controlled schedule — pull requests are reviewed at the maintainer's discretion and timeline.