Writing Data to Neo4j

Your challenge is to modify another pre-written file to add yourself as an actor in The Matrix.

Open Challenge in an Online IDE →

Steps

  1. Update the params object to use your name. This step isn’t strictly required, just a bit of fun.

  2. The Cypher statement is already written for you. Call the session.executeWrite() method, passing a callback function to represent the unit of work.

  3. In that function you must call the run() method on the first parameter passed to the function, using the cypher and params variables.

  4. await the results and use console.log to check that the code has executed correctly.

  5. To add the new node and relationship to the database, click the Debug icon to the left of the window and run Writing Data Challenge task, or use the integrated terminal window to run the following command:

    sh
    Run The Challenge
    ts-node src/challenges/write/challenge.ts
  6. Once the code has run, click Verify and we will check that the node has been added to the database.

Verifying the Test

Once you have executed the code, click the Verify button and we will check that the code has been executed successfully.

Hint

To pass this challenge you must run the Cypher statement in a write transaction using the session.executeWrite() method.

Solution

Compare your code with the solution here

ts
// Import the driver
import neo4j from 'neo4j-driver'
import { getNeo4jCredentials } from '../utils'

// Neo4j Credentials
const {
  NEO4J_URI,
  NEO4J_USERNAME,
  NEO4J_PASSWORD
} = getNeo4jCredentials()

async function main() {
  // Create a Driver Instance
  const driver = neo4j.driver(
    NEO4J_URI,
    neo4j.auth.basic(NEO4J_USERNAME, NEO4J_PASSWORD)
  )

  // Open a new Session
  const session = driver.session()

  try {
    const cypher = `
      MATCH (m:Movie {title: "Matrix, The"})
      CREATE (p:Person {name: $name})
      CREATE (p)-[:ACTED_IN]->(m)
      RETURN p
    `
    const params = { name: 'Your Name' }

    // Execute the `cypher` statement in a write transaction
    const res = await session.executeWrite(
      tx => tx.run(cypher, params)
    )

    console.log(res.records[0].get('p'))
  }
  finally {
    // Close the session
    await session.close()
  }
}

main()

Click here to view the solution on Github

Lesson Summary

In this challenge, you used your knowledge to create a driver instance and run a Cypher statement.

Next, we will look at the Neo4j Type System and some of the considerations that you need to make when working with values coming from Neo4j in your TypeScript application.