memgraph/docs/user_technical/quick-start.md

Quick Start

This chapter outlines several ways to connect and execute openCypher queries against Memgraph using available Bolt clients and drivers.

Before the start, it is important to mention a couple of current limitations. Memgraph doesn't yet support multi-command transactions. In other words, explicit start and termination of transactions isn't yet supported. A transaction is created and committed implicitly before and after each run method.

SSL is also not supported yet, so a driver has to be configured without encryption. This is usually accomplished by modifying the configuration parameters before using them to construct the driver. There should be a parameter controlling the encryption and it should be set to a disabled state. Furthermore, the authorization isn't supported yet. Username and password parameters are ignored during the authorization process. In other words, any combination of username and password will work, preferably they should be empty.

Memgraph is 100% Bolt compliant. That means every Bolt compliant driver should work. The following clients and drivers are tested libneo4j-client (C), neo4j-driver (Python), neo4j-driver (Javascript), Neo4j Driver (Java).

Graph Gists

A nice looking set of small graph examples could be found here. You can take any use-case and try to execute the queries against Memgraph. We welcome your feedback!

neo4j-client Example

Please take a look here for the installation details and complete documentation.

Query execution

You can execute a single query by piping the query string to the client

echo "MATCH (n) RETURN n;" | neo4j-client --insecure -u "" -p "" localhost 7687

or start the client and then make the connection. The most important thing is not to forget --insecure parameter to disable SSL.

neo4j-client --insecure
# to establish a connection the connect command has to be excuted as follows
:connect localhost 7687

Each query written in the neo4j-client console has to be finished with ; e.g.

MATCH ()-[r]->() RETURN count(r);

Python Driver Example

The details about Python driver can be found on GitHub. Below is a very basic example how to execute queries against Memgraph.

Similar to all other drivers, driver and session have to be initialized (at the end of execution they also have to be closed). To execute a query, run method has to be called. consume is here just to block the execution until the query is actually executed. At the end of the code snippet shown below, the print function is used to display properties and labels of the obtained data.

from neo4j.v1 import GraphDatabase, basic_auth

driver = GraphDatabase.driver("bolt://localhost:7687",
                              auth=basic_auth("", ""),
                              encrypted=False)
session = driver.session()

session.run('MATCH (n) DETACH DELETE n').consume()
session.run('CREATE (alice:Person {name: "Alice", age: 22})').consume()

returned_result_set = session.run('MATCH (n) RETURN n').data()
returned_result = returned_result_set.pop()
alice = returned_result["n"]

print(alice['name'])
print(alice.labels)
print(alice['age'])

session.close()
driver.close()

Java Driver Example

The details about Java driver can be found on GitHub.

The example below is equivalent to Python example. Major difference is that Config object has to be created before the driver construction. Encryption has to be disabled by calling withoutEncryption method against the Config builder.

import org.neo4j.driver.v1.*;
import org.neo4j.driver.v1.types.*;
import static org.neo4j.driver.v1.Values.parameters;
import java.util.*;

public class JavaQuickStart {
    public static void main(String[] args) {
        // Init driver.
        Config config = Config.build().withoutEncryption().toConfig();
        Driver driver = GraphDatabase.driver("bolt://localhost:7687",
                                             AuthTokens.basic("",""),
                                             config);
        // Execute basic queries.
        try (Session session = driver.session()) {
            StatementResult rs1 = session.run("MATCH (n) DETACH DELETE n");
            StatementResult rs2 = session.run(
                "CREATE (alice: Person {name: 'Alice', age: 22})");
            StatementResult rs3 = session.run( "MATCH (n) RETURN n");
            List<Record> records = rs3.list();
            Record record = records.get(0);
            Node node = record.get("n").asNode();
            System.out.println(node.get("name").asString());
        } catch (Exception e) {
            System.out.println(e);
            System.exit(1);
        }
        // Cleanup.
        driver.close();
    }
}

Javascript Driver Example

The details about Javascript driver can be found [on GitHub] (https://github.com/neo4j/neo4j-javascript-driver).

The Javascript example below is equivalent to Python and Java examples. SSL can be disabled by passing {encrypted: 'ENCRYPTION_OFF'} during the driver construction.

Here is an example related to Node.js. Memgraph doesn't have integrated support for Web Socket which is required during the execution in any web browser. If you want to run openCypher queries from a web browser, websockify has to be up and running. Requests from web browsers are wrapped into Web Socket messages, and a proxy is needed to handle the overhead. The proxy has to be configured to point out to Memgraph's Bolt port and web browser driver has to send requests to the proxy port.

var neo4j = require('neo4j-driver').v1;
var driver = neo4j.driver("bolt://localhost:7687",
                          neo4j.auth.basic("neo4j", "1234"),
                          {encrypted: 'ENCRYPTION_OFF'});
var session = driver.session();

function die() {
  session.close();
  driver.close();
}

function run_query(query, callback) {
  var run = session.run(query, {});
  run.then(callback).catch(function (error) {
    console.log(error);
    die();
  });
}

run_query("MATCH (n) DETACH DELETE n", function (result) {
  console.log("Database cleared.");
  run_query("CREATE (alice: Person {name: 'Alice', age: 22})", function (result) {
    console.log("Record created.");
    run_query("MATCH (n) RETURN n", function (result) {
      console.log("Record matched.");
      var alice = result.records[0].get("n");
      console.log(alice.labels[0]);
      console.log(alice.properties["name"]);
      session.close();
      driver.close();
    });
  });
});