Build a Node.js App with CockroachDB and Sequelize

Warning:
Cockroach Labs will stop providing Assistance Support for this version on November 12, 2021. Prior to that date, upgrade to a more recent version to continue receiving support. For more details, see the Release Support Policy.

This tutorial shows you how build a simple Node.js application with CockroachDB and the Sequelize ORM.

We have tested the Sequelize ORM enough to claim beta-level support. If you encounter problems, please open an issue with details to help us make progress toward full support.

Tip:

For a more realistic use of Sequelize with CockroachDB, see our examples-ormsrepository.

Step 1. Start CockroachDB

  1. If you haven't already, download the CockroachDB binary.
  2. Run the cockroach demo command:

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    $ cockroach demo \
    --empty
    

    This starts a temporary, in-memory cluster and opens an interactive SQL shell to the cluster.

  3. Take note of the (sql/tcp) connection string in the SQL shell welcome text:

    # Connection parameters:
    #   (console) http://127.0.0.1:61009
    #   (sql)     postgres://root:admin@?host=%2Fvar%2Ffolders%2Fk1%2Fr048yqpd7_9337rgxm9vb_gw0000gn%2FT%2Fdemo255013852&port=26257
    #   (sql/tcp) postgres://root:admin@127.0.0.1:61011?sslmode=require    
    

    You will use it in your application code later.

Step 2. Create a database

  1. In the SQL shell, create the bank database that your application will use:

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    > CREATE DATABASE bank;
    
  2. Create a SQL user for your app:

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    > CREATE USER <username> WITH PASSWORD <password>;
    

    Take note of the username and password. You will use it in your application code later.

  3. Give the user the necessary permissions:

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    > GRANT ALL ON DATABASE bank TO <username>;
    

Step 3. Install the Sequelize ORM

To install Sequelize, as well as a CockroachDB Node.js package that accounts for some minor differences between CockroachDB and PostgreSQL, run the following command:

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$ npm install sequelize sequelize-cockroachdb

Step 4. Get the code

Download the sample code directly, or clone the code's GitHub repository.

Step 5. Update the connection parameters

Open app.js, and edit the connection configuration parameters:

  • Replace the value for username with the user you created earlier.
  • Replace the value for password with the password you created for your user.
  • Replace the value for port with the port to your cluster.
  • At the top of the file, uncomment the const fs = require('fs'); line.

    This line imports the fs Node module, which enables you to read in the CA cert that you downloaded from the CockroachCloud Console.

  • Replace the value for username with the user you created earlier.

  • Replace the value for password with the password you created for your user.

  • Replace the value for host with the name of the CockroachCloud Free host (e.g., host: 'free-tier.gcp-us-central1.cockroachlabs.cloud').

  • Replace the value for port with the port to your cluster.

  • Replace the value for database with the database that you created earlier, suffixed with the name of the cluster (e.g., database: '{cluster_name}.bank').

  • Remove the rejectUnauthorized key-value pair.

  • Uncomment the ca key-value pair, and edit the fs.readFileSync('certs/ca.crt').toString() call to use the path to the cc-ca.crt file that you downloaded from the CockroachCloud Console.

Step 6. Run the code

The following code uses the Sequelize ORM to map Node.js-specific objects to SQL operations. Specifically, Account.sync({force: true}) creates an accounts table based on the Account model (or drops and recreates the table if it already exists), Account.bulkCreate([...]) inserts rows into the table, and Account.findAll() selects from the table so that balances can be printed.

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const Sequelize = require("sequelize-cockroachdb");
// For secure connection:
//const fs = require('fs');

// Connect to CockroachDB through Sequelize.
var sequelize = new Sequelize({
  dialect: "postgres",
  username: "max",
  password: "roach",
  host: "localhost",
  port: 26257,
  database: "bank",
  dialectOptions: {
    ssl: {
      rejectUnauthorized: false,
      // For secure connection:
      /*ca: fs.readFileSync('certs/ca.crt')
                .toString()*/
    },
  },
  logging: false,
});

// Define the Account model for the "accounts" table.
const Account = sequelize.define("accounts", {
  id: {
    type: Sequelize.INTEGER,
    primaryKey: true,
  },
  balance: {
    type: Sequelize.INTEGER,
  },
});

// Create the "accounts" table.
Account.sync({
  force: true,
})
  .then(function () {
    // Insert two rows into the "accounts" table.
    return Account.bulkCreate([
      {
        id: 1,
        balance: 1000,
      },
      {
        id: 2,
        balance: 250,
      },
    ]);
  })
  .then(function () {
    // Retrieve accounts.
    return Account.findAll();
  })
  .then(function (accounts) {
    // Print out the balances.
    accounts.forEach(function (account) {
      console.log(account.id + " " + account.balance);
    });
    process.exit(0);
  })
  .catch(function (err) {
    console.error("error: " + err.message);
    process.exit(1);
  });

To run the code:

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$ node app.js

The output should be:

1 1000
2 250

What's next?

Read more about using the Sequelize ORM, or check out a more realistic implementation of Sequelize with CockroachDB in our examples-orms repository.

You might also be interested in the following pages:

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