Unit 4 Chapter 2: Rails App With SQLite

In this chapter, you will create a Rails app that uses SQLite as the database.

Topics Covered

• Creating a new Rails app that uses SQLite for the database
• Viewing the Rails app in your web browser
• Viewing your Rails app's database with the SQLite Browser

Creating and Viewing the App

• From the same rvm-rails-general directory you used to enter Docker in the previous chapter, enter the command "sh reset.sh" to return to Docker.
• Enter the following command:

sh test-rails-sq.sh

• The process of creating the new app will take a few minutes. (This script follows the procedure from http://elinux.org/RPi_Ruby_on_Rails for creating a new Rails app.) When it is finished, open your web browser, and go to the URL http://localhost:3010/pupils . You should now see a form called "Pupils".

Adding Pupils

• Click on "New Pupil". For the name, enter "Rod Serling". For the form, enter "The Twilight Zone". Click on "Create Pupil". Click on "Back".
• Click on "New Pupil". For the name, enter "George Romero". For the form, enter "Tales from the Darkside". Click on "Create Pupil". Click on "Back".
• You should now see both of these pupils listed on the web page.

Using SQLite Browser

• In your desktop Linux system, open SQLiteBrowser (which is automatically installed during the official Docker installation process). Go to File -> Open Database, and open the db/development.sqlite3 file within your app. (The directory tree is rubyonracetracks -> docker-debian-buster-use -> rvm-rails-general -> shared -> school_sq .)
• Go to the "Browse Data" tab.
• Change the "Table" setting to display "pupils".
• You should now see the entries for Rod Serling and George Romero.

Exiting

• Exit SQLite Browser.
• In Docker, press Ctrl-C to stop the local server so that you can continue entering commands.
• Enter the command "exit".
• In the next chapter, you will create a basic Ruby on Rails app that uses PostgreSQL instead of SQLite as the database.