JavaScript Driver Basics for Neo4j

Introduction

The Neo4j JavaScript driver provides a way to connect to and interact with a Neo4j database using JavaScript. This lesson covers the basics of using the Neo4j JavaScript driver, including installation, connecting to the database, and executing queries.

Installation

To install the Neo4j JavaScript driver, you can use npm. Run the following command in your terminal:

npm install neo4j-driver

Make sure you have Node.js installed on your machine to use npm.

Connecting to Neo4j

To connect to a Neo4j database, you need to import the driver and create a session. Below is a step-by-step process:

1. Import the Neo4j driver.
2. Create a driver instance with the connection URI and credentials.
3. Open a session from the driver instance.
4. Execute your queries within the session.
5. Close the session and driver after use.

Here is an example code snippet:

const neo4j = require('neo4j-driver');

const driver = neo4j.driver("bolt://localhost:7687", 
    neo4j.auth.basic("username", "password"));
const session = driver.session();

session.run("MATCH (n) RETURN n LIMIT 5")
    .then(result => {
        result.records.forEach(record => {
            console.log(record.get('n'));
        });
    })
    .catch(error => {
        console.error(error);
    })
    .finally(() => {
        session.close();
        driver.close();
    });
                

Basic Queries

Neo4j uses Cypher as its query language. Below are some basic examples of executing queries with the JavaScript driver:

1. Retrieving nodes:

session.run("MATCH (n) RETURN n").then(...);

2. Creating nodes:

session.run("CREATE (n:Person {name: 'Alice'})").then(...);

3. Updating nodes:

session.run("MATCH (n:Person {name: 'Alice'}) SET n.age = 30").then(...);

4. Deleting nodes:

session.run("MATCH (n:Person {name: 'Alice'}) DELETE n").then(...);

Best Practices

• Always close your sessions and drivers to avoid memory leaks.
• Use transactions for multiple queries to ensure consistency.
• Handle errors gracefully to avoid crashing your application.
• Optimize your Cypher queries for better performance.

FAQ