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https://github.com/opencypher/cypher-for-gremlin
Cypher for Gremlin adds Cypher support to any Gremlin graph database.
https://github.com/opencypher/cypher-for-gremlin
cypher graph gremlin tinkerpop tinkerpop3
Last synced: about 2 months ago
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Cypher for Gremlin adds Cypher support to any Gremlin graph database.
- Host: GitHub
- URL: https://github.com/opencypher/cypher-for-gremlin
- Owner: opencypher
- License: apache-2.0
- Created: 2018-01-24T13:27:48.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2020-06-07T11:24:58.000Z (over 4 years ago)
- Last Synced: 2024-06-22T05:05:18.063Z (3 months ago)
- Topics: cypher, graph, gremlin, tinkerpop, tinkerpop3
- Language: Java
- Size: 18.5 MB
- Stars: 353
- Watchers: 24
- Forks: 48
- Open Issues: 35
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
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README
# Cypher for Gremlin
[](https://circleci.com/gh/opencypher/cypher-for-gremlin)
[](https://search.maven.org/#search%7Cga%7C1%7Corg.opencypher.gremlin)
Cypher for Gremlin is a toolkit for users of [Apache TinkerPop™](https://tinkerpop.apache.org/) that allows querying Gremlin databases with [Cypher](https://neo4j.com/docs/developer-manual/current/cypher/), the industry's most widely used [property graph](https://github.com/opencypher/openCypher/blob/master/docs/property-graph-model.adoc) query language defined and maintained by the [openCypher](http://www.opencypher.org) project.
Cypher query is translated to one of Gremlin representations (Gremlin Groovy string, Traversal object or Gremlin bytecode):
## Table of Contents
* [Overview](#overview)
* [Highlights](#highlights)
* [Quick Start](#quick-start)
* [Toolkit](#toolkit)
* [Language Support](#language-support)
* [Related](#related)
* [Implementation](#implementation)
* [Development](#development)
* [How to contribute](#how-to-contribute)
* [License](#license)
* [Copyright](#copyright)
## Overview
## Highlights
### Gremlin Console Plugin
[Gremlin Console plugin](tinkerpop/cypher-gremlin-console-plugin) that enables client-side translation of Cypher queries
or communication with a Cypher-enabled Gremlin Server (click to play/[view source](testware/integration-tests/src/test/resources/snippets/console-demo.out)):
### Gremlin Server Client
[Gremlin Server client](tinkerpop/cypher-gremlin-server-client) wrapper that can send Cypher queries to a Cypher-enabled Gremlin Server or translate Cypher queries to Gremlin on client side, and send translated query to servers:
```java
String cypher = "MATCH (p:person) WHERE p.age > 25 RETURN p.name";
Cluster cluster = Cluster.open(configuration);
Client gremlinClient = cluster.connect();
// Server has Gremlin Server plugin installed
// Send Cypher to server
CypherGremlinClient cypherGremlinClient = CypherGremlinClient.plugin(gremlinClient);
List> cypherResults = cypherGremlinClient.submit(cypher).all();
// Client side translation
// Send Gremlin to server
CypherGremlinClient translatingGremlinClient = CypherGremlinClient.translating(gremlinClient);
List> gremlinResults = translatingGremlinClient.submit(cypher).all();
assertThat(cypherResults).isEqualTo(gremlinResults);
```
### Gremlin Neo4j Driver
[Implementation of Neo4j API interfaces](tinkerpop/cypher-gremlin-neo4j-driver) for users familiar with Neo4j:
```java
Driver driver = GremlinDatabase.driver(uri);
try (Session session = driver.session()) {
StatementResult result = session.run("MATCH (n) RETURN count(n) as count");
int n = result.single().get("count").asInt();
assertThat(n).isEqualTo(0); // 0
}
```
### Gremlin Server Plugin
[Gremlin Server plugin](tinkerpop/cypher-gremlin-server-plugin) that enables Cypher query processing on Gremlin Server. For example connect using [Gremlin-JavaScript](http://tinkerpop.apache.org/docs/current/reference/#gremlin-javascript) 3.4.2+ by setting `processor` to `cypher`:
```js
// npm install [email protected]
const gremlin = require('gremlin');
const client = new gremlin.driver.Client('ws://localhost:8182/gremlin', { traversalSource: 'g', processor: 'cypher'});
const cypherQuery = 'MATCH (n) RETURN n.name'
const results = await client.submit(cypherQuery);
for (const result of results) {
console.log(result);
}
```
See examples for [Gremlin-Java](tinkerpop/cypher-gremlin-server-plugin#gremlin-javagremlin-groovy), [Gremlin-Groovy](tinkerpop/cypher-gremlin-server-plugin#gremlin-javagremlin-groovy), [Gremlin-Python](tinkerpop/cypher-gremlin-server-plugin#gremlin-python) and [Gremlin.Net](tinkerpop/cypher-gremlin-server-plugin#gremlinnet)
### Cypher Traversal Source
For [Gremlin Console Plugin](https://github.com/opencypher/cypher-for-gremlin/tree/master/tinkerpop/cypher-gremlin-console-plugin#combining-cypher-and-gremlin) and [Gremlin Server Client](https://github.com/opencypher/cypher-for-gremlin/tree/master/tinkerpop/cypher-gremlin-server-client#cypher-traversal-source)
its possible to combine Cypher and Gremlin in single query. Traversal can start with `cypher` step that allows to run Cypher
query (which will be translated to Gremlin and works `withRemote`) then continue traversal using other Gremlin steps:
```java
CypherTraversalSource g = graph.traversal(CypherTraversalSource.class);
GraphTraversal, String> query = g
.cypher("MATCH (n) RETURN n")
.select("n")
.outE()
.label()
.dedup();
```
## Quick Start
1. Run [Docker images](docker)
2. Start experimenting with Cypher for Gremlin with the [Gremlin Console Cypher plugin](tinkerpop/cypher-gremlin-console-plugin). Follow the link for installation and usage instructions.
3. For API usage take a look at the [Cypher for Gremlin Demo](https://github.com/neueda/cypher-for-gremlin-demo) project.
## Toolkit
The toolkit is composed of:
- [translation](translation): Cypher to Gremlin translation library for Java
- [tinkerpop/cypher-gremlin-extensions](tinkerpop/cypher-gremlin-extensions): Extensions to Gremlin to enable full support for Cypher functionality
- [tinkerpop/cypher-gremlin-server-plugin](tinkerpop/cypher-gremlin-server-plugin): Gremlin Server plugin that enables Cypher query processing (also includes extensions above)
- [tinkerpop/cypher-gremlin-console-plugin](tinkerpop/cypher-gremlin-console-plugin): Gremlin Console plugin that enables client-side translation of Cypher queries or communication with a Cypher-enabled Gremlin Server
- [tinkerpop/cypher-gremlin-server-client](tinkerpop/cypher-gremlin-server-client): Gremlin Server client wrapper that can send Cypher queries to a Cypher-enabled Gremlin Server
- [tinkerpop/cypher-gremlin-neo4j-driver](tinkerpop/cypher-gremlin-neo4j-driver): Neo4j Java API wrapper for users familiar with Neo4j
## Language Support
With Cypher for Gremlin you can use the following Cypher language features:
- `MATCH` and `OPTIONAL MATCH`
- `WHERE`, `ORDER BY`, `SKIP`, and `LIMIT` sub-clauses
- `RETURN`, `WITH`, and `UNWIND` projections, including basic support for list and path comprehensions
- `CREATE`, `MERGE`, `SET`, `REMOVE`, and `(DETACH) DELETE`
- `CASE` expressions
- `UNION (ALL)` operations
- `CALL` procedures
It is not guaranteed that all instances and combinations of the listed features will work. However, in addition to [integration tests](testware), correctness of translation is verified by the [Cypher Technology Compatibility Kit](https://github.com/opencypher/openCypher/tree/master/tck) (TCK). The TCK is an openCypher artifact and contains a comprehensive set of test scenarios validating different features of the Cypher language.
Coverage of TCK M13 ([excluding Temporal Types](tinkerpop/cypher-gremlin-extensions#temporal-types)) on TinkerGraph:
- 75% of the scenarios are supported with common Gremlin steps
- Additional 15% with [extensions](tinkerpop/cypher-gremlin-extensions) to Gremlin to enable full support for Cypher functionality
- See [latest TCK Report](https://opencypher.github.io/cypher-for-gremlin/test-reports/1.0.4/cucumber-html-reports/overview-features.html) for a detailed overview of language coverage.
You are very welcome to report any [issues](https://github.com/opencypher/cypher-for-gremlin/issues) with the translation that you encounter.
### Gremlin Implementations
Cypher for Gremlin is tested on following Gremlin implementations:
* With [Gremlin Extensions for Cypher Support](https://github.com/opencypher/cypher-for-gremlin/tree/master/tinkerpop/cypher-gremlin-extensions)
- [TinkerGraph](https://github.com/opencypher/cypher-for-gremlin/wiki/Gremlin-implementations#tinkergraph-with-gremlin-extensions-for-cypher-support)
- [JanusGraph](https://github.com/opencypher/cypher-for-gremlin/wiki/Gremlin-implementations#janusgraph-with-cypher-plugin)
- [Neo4j-Gremlin](https://github.com/opencypher/cypher-for-gremlin/wiki/Gremlin-implementations#neo4j-gremlin-with-cypher-plugin)
* Without extensions
- [TinkerGraph](https://github.com/opencypher/cypher-for-gremlin/wiki/Gremlin-implementations#tinkergraph)
- [Neptune](https://github.com/opencypher/cypher-for-gremlin/wiki/Gremlin-implementations#neptune) with `neptune` [flavor](https://github.com/opencypher/cypher-for-gremlin/wiki/Gremlin-implementations#flavors)
- [CosmosDB](https://github.com/opencypher/cypher-for-gremlin/wiki/Gremlin-implementations#cosmos-db) with `cosmosDb` [flavor](https://github.com/opencypher/cypher-for-gremlin/wiki/Gremlin-implementations#flavors)
Each Gremlin implementation has its own level of Gremlin support and Gremlin step implementation specifics. In some cases, queries need to be adapted for target implementation using [flavor](https://github.com/opencypher/cypher-for-gremlin/wiki/Gremlin-implementations#flavors).
Because of these specifics, Cypher support varies on different implementations. Refer to [wiki](https://github.com/opencypher/cypher-for-gremlin/wiki/Gremlin-implementations) for more details.
## Related
* [Gizmo](https://github.com/rebar-cloud/gizmo) is a Web UI that makes it easy to interact with TinkerPop graph databases such as AWS Neptune and Azure CosmosDB with the Cypher query language. Uses [Cypher Gremlin Neo4j Driver](tinkerpop/cypher-gremlin-neo4j-driver) for translation.
* [Graph Database support plugin for JetBrains](https://github.com/neueda/jetbrains-plugin-graph-database-support) allows you to work with Tinkerpop and Neo4j databases using Cypher without leaving IDE. Uses [Cypher for Gremlin](translation) for translation.
## Implementation
The translation process uses a reasonably sophisticated and flexible approach. Cypher query is parsed by the [openCypher Frontend](https://github.com/opencypher/front-end) and translated to an [internal representation](translation/src/main/scala/org/opencypher/gremlin/translation/ir/model) by the Cypher for Gremlin. The internal representation is transformed by a set of [rewriters](translation/src/main/scala/org/opencypher/gremlin/translation/ir/rewrite) to adapt the query for system specifics of different Gremlin implementations (JanusGraph, Cosmos DB, AWS Neptune), then converted to one of Gremlin representations (Gremlin Groovy string, Traversal object or Gremlin bytecode).
See also [How to implement new Cypher feature?](https://github.com/opencypher/cypher-for-gremlin/wiki/How-to-implement-new-Cypher-feature%3F)
## Development
To build and run Cypher for Gremlin you need Java 8.
The project is built using [Gradle](https://gradle.org/) or the provided wrapper.
To build and run unit and integration tests:
```
./gradlew build
```
To automatically fix formatting errors in your changes:
```
./gradlew spotlessApply
```
## How to contribute
We would love to find out about any [issues](https://github.com/opencypher/cypher-for-gremlin/issues) you encounter and are happy to accept contributions following a Contributors License Agreement (CLA) signature as per the process outlined in our [contribution guidelines](CONTRIBUTING.md).
## License
The project is licensed under the Apache Software License, Version 2.0
## Copyright
© Copyright 2018-2019 Neo4j, Inc.
Apache TinkerPop™, TinkerPop, and Apache are registered trademarks of the [Apache Software Foundation](https://www.apache.org/).