Type definitions in GraphQL - Mini Project: Build & Apply

GraphQL Type Definitions for a Bookstore

📖 Scenario: You are building a simple online bookstore API using GraphQL. You need to define the data types that describe books and authors so the API can understand the structure of the data it will handle.

🎯 Goal: Create GraphQL type definitions for Book and Author that include fields with specific types. Then add a query type to fetch books and authors.

📋 What You'll Learn

Define a Book type with fields: id (ID!), title (String!), author (Author!)

Define an Author type with fields: id (ID!), name (String!)

Create a Query type with fields: books (list of Book), authors (list of Author)

💡 Why This Matters

🌍 Real World

GraphQL type definitions are essential for building APIs that clients can query to get exactly the data they need.

💼 Career

Defining clear and correct GraphQL schemas is a key skill for backend developers working with modern APIs.

1

Define the Book type

Create a GraphQL type called Book with these exact fields: id of type ID!, title of type String!, and author of type Author!.

GraphQL

# Define the Book type with id, title, and author fields
# Your code here

Need a hint?

Use type Book { ... } syntax. Remember to use ! to mark fields as required.

2

Define the Author type

Add a GraphQL type called Author with these exact fields: id of type ID! and name of type String!.

GraphQL

type Book {
  id: ID!
  title: String!
  author: Author!
}

# Define the Author type with id and name fields
# Your code here

Need a hint?

Use the same syntax as the Book type but with the Author fields.

3

Create the Query type

Add a GraphQL Query type with these exact fields: books which returns a list of Book (use square brackets), and authors which returns a list of Author.

GraphQL

type Book {
  id: ID!
  title: String!
  author: Author!
}

type Author {
  id: ID!
  name: String!
}

# Define the Query type with books and authors fields
# Your code here

Need a hint?

Use square brackets [] to indicate a list of items in GraphQL.

4

Complete the schema with schema definition

Add the GraphQL schema definition that sets the query root type to the Query type you created.

GraphQL

type Book {
  id: ID!
  title: String!
  author: Author!
}

type Author {
  id: ID!
  name: String!
}

type Query {
  books: [Book]
  authors: [Author]
}

# Add the schema definition linking query to Query type
# Your code here

Need a hint?

The schema block tells GraphQL which type is the root query type.