Nested objects and arrays in Firebase - Mini Project: Build & Apply

Nested objects and arrays

📖 Scenario: You are setting up a Firebase Firestore database for a small online bookstore. You want to organize the data so that each book document contains nested information about the author and an array of reviews.

🎯 Goal: Create a Firestore document structure with nested objects for author details and an array of review objects inside a book document.

📋 What You'll Learn

Create a Firestore document called book with nested author information

Include an array called reviews inside the book document

Each review in the reviews array should be an object with reviewer and comment fields

Use valid Firestore data types and structure

💡 Why This Matters

🌍 Real World

Organizing complex data like books with authors and reviews in Firestore for a real online bookstore.

💼 Career

Understanding nested data structures and arrays in Firestore is essential for backend cloud developers working with NoSQL databases.

1

Create the initial book document with title and author nested object

Create a Firestore document called book with a title field set to "The Great Gatsby" and a nested author object containing name set to "F. Scott Fitzgerald" and birthYear set to 1896.

Firebase

# Your code here

Need a hint?

Use a dictionary with a nested dictionary for the author.

2

Add an empty reviews array to the book document

Add an empty array called reviews to the existing book document.

Firebase

book = {
    "title": "The Great Gatsby",
    "author": {
        "name": "F. Scott Fitzgerald",
        "birthYear": 1896
    },
    # Add the reviews array here
}

Need a hint?

Add a key "reviews" with an empty list as its value.

3

Add two review objects to the reviews array

Add two review objects to the reviews array inside the book document. The first review should have reviewer set to "Alice" and comment set to "Loved the vivid characters.". The second review should have reviewer set to "Bob" and comment set to "A timeless classic.".

Firebase

book = {
    "title": "The Great Gatsby",
    "author": {
        "name": "F. Scott Fitzgerald",
        "birthYear": 1896
    },
    "reviews": [
        # Add two review objects here
    ]
}

Need a hint?

Each review is a dictionary inside the list assigned to reviews.

4

Complete the Firestore document structure for deployment

Assign the book dictionary to a Firestore document reference called doc_ref using the method set() to save the data. Assume db is your Firestore client and the collection is called books. Write the line of code that sets the document with ID gatsby.

Firebase

book = {
    "title": "The Great Gatsby",
    "author": {
        "name": "F. Scott Fitzgerald",
        "birthYear": 1896
    },
    "reviews": [
        {"reviewer": "Alice", "comment": "Loved the vivid characters."},
        {"reviewer": "Bob", "comment": "A timeless classic."}
    ]
}

# Add the Firestore set() call below

Need a hint?

Use db.collection("books").document("gatsby") to get the document reference, then call set(book).