Ruby on Rails: Database Setup

Database Configuration

Once we’ve created our project, open that project in your preferred IDE. It’ll look something like this.

Here, we’ve used Visual Studio.

To work with databases in Ruby on Rails, we’ve to configure our database first. All the configuration related files are present in the config directory. Inside that config directory, there is a file named database.yml. 

When we open this database.yml file in a new rails application, we’ll see a default database configuration using SQLite. 

This file contains sections for three different environments in which Rails can run by default. These three sections are:

1. Development: This environment is used on our development computer as we manually interact with the application.
2. Test: This environment is used to run automated tests.
3. Production: This environment is used when we deploy our application.

All we have to do is create three different databases for these three environments. Next, we should initialize all three and assign them a user and password with full read and write privileges.

Configuring SQLite Database

Ruby on Rails includes SQLite support, a lightweight serverless database application. While SQLite may become overloaded in a busy production environment, it is ideal for development and testing. When you create a new project in Rails, it defaults to using SQLite database, but you can always change it later.

The following code contains the default configuration file containing the SQLite database's connection information.

# SQLite version 3.x
default: &default
  adapter: sqlite3
  pool: 5
  timeout: 5000

development:
  <<: *default
  database: db/development.sqlite3

test:
  <<: *default
  database: db/test.sqlite3

production:
  <<: *default
  database: db/production.sqlite3

If you want to change your database, all you have to do is make changes in that database.yml file. This file contains live database configuration sections. Let’s see the configuration of the MySQL database.

Configuring a MySQL Database

For setting up MySQL, we have to install MySQL and check if it is running correctly. 

In the next step, we must inform the MySQL database's user name and password that we've set during installation to Ruby on Rails. In this example, we'll be using the root user ID.

So, in the database.yml file, add username and password just like in the configuration snippet given below. Change the username and password lines in each section you use to reflect the permissions on the databases you've created.
 

#For MySQl
default: &default
  adapter: mysql2
  database: basicblog_development
  username: root
  password: [password]
  host: localhost
  port: 3306

development:
   adapter: mysql2
   database: basicblog_development
   username: root
   password: [password]
   host: localhost
 
test:
   adapter: mysql2
   database: basicblog_test
   username: root
   password: [password]
   host: localhost
   
production:
   adapter: mysql2
   database: basicblog_production
   username: root
   password: [password]
   host: localhost

Save the file, and you are good to go.

Now, let’s see how this works for PostgreSQL.

Configuring PostgreSQL Database

A PostgreSQL database will be a more robust and flexible choice for highly complex applications that require more reliable data integrity and programmatic extensibility.  

To get your Ruby on Rails setup up and running with PostgreSQL, you'll need to take a few extra steps.

For setting up PostgreSQL, we have to install PostgreSQL and check if it is running correctly. During the installation, PostgreSQL does not provide any user. So, we have to create a superuser. 

Below is the command to create a user, substituting the highlighted word with the username.

sudo -u postgres createuser -s vaishnavi -P

You will be prompted to enter a password for your new role because you specified the -P flag. Enter your desired password, making a note of it to use in a configuration file in a later step.

You used createuser to create a user in this command. The -s option granted this user superuser privileges, and sudo -u allowed you to run the command from the postgres account, which is created automatically when you install PostgreSQL.

Now, it's time to make changes to the database.yml file. Add the user and password in the file as given below.
 

#For PostgreSQl
default: &default
   adapter: postgresql
   encoding: unicode
 
development:
   adapter: postgresql
   encoding: unicode
   database: basicblog_development
   username: vaishnavi
   password: [password]

test:
   adapter: postgresql
   encoding: unicode
   database: basicblog_test
   username: vaishnavi
   password: [password]
 
production:
   adapter: postgresql
   encoding: unicode
   database: basicblog_production
   username: vaishnavi
   password: [password]

Save this file, and you are done. 

This was all about setting up various databases in Ruby on Rails. Let’s move to some of the frequently asked questions on this topic.

FAQs

1. Which is the default database of Ruby on Rails?
   Our application is set up by default to use SQLite as a database in Ruby on Rails.
    
2. What are the two essential prerequisites of setting up a database in Rails?
   The two main prerequisites are:
   A live running server.
   Ruby on Rails development environment.

Key Takeaways

This article ran you through the basic Database setup in the Ruby on Rails framework. Understanding how its database works is essential for getting started with a framework. 

You can also read blogs on other Ruby on Rails topics such as Views, Controllers and Migrations. 

Keep Learning with Coding Ninjas!