Seed data in Ruby on Rails - Mini Project: Build & Apply

Seed Data in Rails

📖 Scenario: You are building a simple Rails app to manage a bookstore. You want to add some initial books to your database so you can see them when you run the app.

🎯 Goal: Create seed data for the Book model with exact titles and authors. Then configure a count variable to track how many books you add. Finally, write the code to insert these books into the database using Rails seed conventions.

📋 What You'll Learn

Create a list of books with exact titles and authors

Add a variable to count the number of books

Use a loop to create each book record in the database

Ensure the seed file ends with a message showing how many books were added

💡 Why This Matters

🌍 Real World

Seed data helps you quickly fill your app's database with useful starting information, so you can test and develop features without manual data entry.

💼 Career

Knowing how to write seed files is important for backend and full-stack developers working with Rails to set up databases efficiently.

1

Create the books list

Create a variable called books that holds an array of hashes. Each hash should have the keys :title and :author with these exact entries: { title: 'The Great Gatsby', author: 'F. Scott Fitzgerald' }, { title: '1984', author: 'George Orwell' }, and { title: 'To Kill a Mockingbird', author: 'Harper Lee' }.

Ruby on Rails

# Create the books array with hashes for title and author
# Your code here

Need a hint?

Use an array [] with hashes {} inside. Each hash needs :title and :author keys.

2

Add a book count variable

Create a variable called book_count and set it to 0. This will keep track of how many books you add to the database.

Ruby on Rails

books = [
  { title: 'The Great Gatsby', author: 'F. Scott Fitzgerald' },
  { title: '1984', author: 'George Orwell' },
  { title: 'To Kill a Mockingbird', author: 'Harper Lee' }
]
# Create book_count variable and set to 0
# Your code here

Need a hint?

Just write book_count = 0 below the books array.

3

Create books in the database

Use a books.each do |book| loop to create each book in the database with Book.create!(title: book[:title], author: book[:author]). Inside the loop, increase book_count by 1 using book_count += 1.

Ruby on Rails

books = [
  { title: 'The Great Gatsby', author: 'F. Scott Fitzgerald' },
  { title: '1984', author: 'George Orwell' },
  { title: 'To Kill a Mockingbird', author: 'Harper Lee' }
]

book_count = 0

# Loop over books and create each one, increment book_count
# Your code here

Need a hint?

Use books.each do |book| ... end and inside call Book.create! with the right keys. Don't forget to add book_count += 1.

4

Add a completion message

Add a final line that outputs a message with puts showing exactly: "Added #{book_count} books to the database."

Ruby on Rails

books = [
  { title: 'The Great Gatsby', author: 'F. Scott Fitzgerald' },
  { title: '1984', author: 'George Orwell' },
  { title: 'To Kill a Mockingbird', author: 'Harper Lee' }
]

book_count = 0

books.each do |book|
  Book.create!(title: book[:title], author: book[:author])
  book_count += 1
end

# Add a puts line to show how many books were added
# Your code here

Need a hint?

Use puts with double quotes and #{book_count} inside to show the number.