Index creation in Ruby on Rails - Mini Project: Build & Apply

Creating Indexes in Rails Migrations

📖 Scenario: You are building a Rails application to manage a library. The database has a table called books with columns for title, author, and published_year. To make searching faster, you want to add an index on the author column.

🎯 Goal: Learn how to create a database index on a column using a Rails migration to speed up queries on the author field.

📋 What You'll Learn

Create a migration file to add an index on the author column of the books table

Define a variable for the table name

Use the add_index method in the migration

Complete the migration class with the change method

💡 Why This Matters

🌍 Real World

Indexes speed up database searches, making apps faster and more responsive.

💼 Career

Knowing how to create indexes in Rails migrations is essential for backend developers working with databases.

1

Create a migration class named AddIndexToBooksAuthor

Create a migration class called AddIndexToBooksAuthor that inherits from ActiveRecord::Migration[7.0].

Ruby on Rails

# Your code here

Need a hint?

Start by defining the migration class with the correct name and inheritance.

2

Define a variable table_name with value :books

Inside the AddIndexToBooksAuthor class, define a variable called table_name and set it to the symbol :books.

Ruby on Rails

class AddIndexToBooksAuthor < ActiveRecord::Migration[7.0]
  # Define table_name variable
  # Your code here
end

Need a hint?

Use a constant inside the class to set TABLE_NAME.

3

Add the change method with add_index on author

Add a change method inside the AddIndexToBooksAuthor class. Inside it, call add_index with TABLE_NAME and the column :author.

Ruby on Rails

class AddIndexToBooksAuthor < ActiveRecord::Migration[7.0]
  TABLE_NAME = :books

  # Define change method with add_index
  # Your code here
end

Need a hint?

The change method is where you add the index using add_index.

4

Complete the migration class with proper indentation and syntax

Ensure the migration class AddIndexToBooksAuthor has the TABLE_NAME variable, the change method, and the add_index call with correct Ruby syntax and indentation.

Ruby on Rails

class AddIndexToBooksAuthor < ActiveRecord::Migration[7.0]
  TABLE_NAME = :books

  def change
    add_index TABLE_NAME, :author
  end
end
# Your code here

Need a hint?

Check your class structure and indentation carefully.