Database folder and migrations in Ruby on Rails - Mini Project: Build & Apply

Database Folder and Migrations in Rails

📖 Scenario: You are building a simple Rails application to manage a list of books. Each book has a title and an author.

🎯 Goal: Create the initial database setup by defining the database folder structure and writing a migration to create a books table with title and author columns.

📋 What You'll Learn

Create the db folder structure with migrate subfolder

Create a migration file to create a books table

Add title and author columns as strings in the migration

Write the migration class with change method

Ensure the migration file name follows Rails timestamp naming convention

💡 Why This Matters

🌍 Real World

Rails applications use migrations to manage database schema changes safely and consistently across development, testing, and production environments.

💼 Career

Understanding migrations is essential for Rails developers to create and modify database tables, enabling them to build data-driven web applications.

1

Create the database folder structure

Create a folder named db and inside it create a folder named migrate to hold migration files.

Ruby on Rails

# Create folders db and db/migrate in your Rails project directory
# Your code here

Need a hint?

Rails stores migration files inside db/migrate folder.

2

Create a migration file for books table

Create a migration file named 20240101000000_create_books.rb inside db/migrate folder. The filename must start with a timestamp like 20240101000000 followed by _create_books.rb.

Ruby on Rails

# Create file 20240101000000_create_books.rb inside db/migrate
# Your code here

Need a hint?

Migration files are Ruby classes inheriting from ActiveRecord::Migration.

3

Add columns to the books table in migration

Inside the change method of CreateBooks migration, write code to create a books table with string columns title and author using create_table :books do |t| block.

Ruby on Rails

# Add create_table block inside change method
# Your code here

Need a hint?

Use create_table :books do |t| and inside the block add t.string :title and t.string :author.

4

Complete the migration file

Ensure the migration file 20240101000000_create_books.rb contains the full class CreateBooks inheriting from ActiveRecord::Migration[7.0] with the change method that creates the books table with title and author columns.

Ruby on Rails

# Verify the migration class and change method are complete
# Your code here

Need a hint?

The migration class should be complete with the change method creating the table and columns.