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Docs/Getting Started/Ruby on Rails

Connect a Ruby on Rails application to Neon Postgres

Set up a Neon project in seconds and connect from a Ruby on Rails application

Ruby on Rails, also known simply as Rails, is an open-source web application framework written in Ruby. It uses a model-view-controller architecture, making it a good choice for developing database-backed web applications. This guide shows how to connect to a Ruby on Rails application to a Neon Postgres database.

To connect to Neon from a Ruby on Rails application:

  1. Create a Neon Project
  2. Create a Rails Project
  3. Configure a PostgreSQL Database using Rails
  4. Create a Rails Controller
  5. Run the application

This guide was tested using Ruby v3.3.0 and Rails v7.1.2.

Create a Neon Project

If you do not have one already, create a Neon project.

  1. Navigate to the Projects page in the Neon Console.
  2. Click New Project.
  3. Specify your project settings and click Create Project.

Create a Rails Project

Create a Rails project using the Rails CLI, and specify PostgreSQL as the database type:

gem install rails
rails new neon-with-rails --database=postgresql

You now have a Rails project in a folder named neon-with-rails.

Configure a PostgreSQL Database using Rails

Create a .env file in the root of your Rails project, and add the connection string for your Neon compute. Do not specify a database name after the forward slash in the connection string. Rails will choose the correct database depending on the environment.

DATABASE_URL=postgresql://[user]:[password]@[neon_hostname]/

note

You can find the connection string for your database in the Connection Details widget on the Neon Dashboard. For more information, see Connect from any application.

important

The role you specified in the DATABASE_URL must have CREATEDB privileges. Roles created in the Neon Console, CLI, or API, including the default role created with a Neon project, are granted membership in the neon_superuser role, which has the CREATEDB privilege. Alternatively, you can create roles with SQL to grant specific privileges. See Manage database access.

Create the development database by issuing the following commands from the root of your project directory:

# Load the DATABASE_URL into your session
source .env

# Create the development database
bin/rails db:create

Create a Rails Controller to Query the Database

Run the following command to create a controller and view. The controller will query the database version and supply it to the view file to render a web page that displays the PostgreSQL version.

rails g controller home index

Replace the controller contents at app/controllers/home_controller.rb with:

class HomeController < ApplicationController
  def index
    @version = ActiveRecord::Base.connection.execute("SELECT version();").first['version']
  end
end

Replace the contents of the view file at app/views/home/index.html.erb with:

<% if @version %>
  <p><%= @version %></p>
<% end %>

Replace the contents of config/routes.rb with the following code to serve your home view as the root page of the application:

Rails.application.routes.draw do.
  get "up" => "rails/health#show", as: :rails_health_check

  # Defines the root path route ("/")
  root 'home#index'
end

Run the application

Start the application using the Rails CLI from the root of the project:

bin/rails server -e development

Visit localhost:3000/ in your web browser. Your Neon database's Postgres version will be displayed. For example:

PostgreSQL 15.5 on x86_64-pc-linux-gnu, compiled by gcc (Debian 10.2.1-6) 10.2.1 20210110, 64-bit

Schema migration with Ruby on Rails

For schema migration with Ruby on Rails, see our guide:

Need help?

Join our Discord Server to ask questions or see what others are doing with Neon. Users on paid plans can open a support ticket from the console. For more details, see Getting Support.

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