Document ID strategies in Firebase - Mini Project: Build & Apply

Document ID strategies

📖 Scenario: You are building a simple app that stores user profiles in a Firebase Firestore database. Each user profile needs a unique document ID. You want to learn different ways to assign these document IDs when adding data to Firestore.

🎯 Goal: Learn how to create Firestore documents with different document ID strategies: auto-generated IDs, custom string IDs, and using user emails as IDs.

📋 What You'll Learn

Create a Firestore collection called users.

Add a user document with an auto-generated ID.

Add a user document with a custom string ID.

Add a user document using the user's email as the document ID.

💡 Why This Matters

🌍 Real World

In real apps, choosing the right document ID strategy helps organize data and makes it easier to find and update records.

💼 Career

Understanding Firestore document IDs is essential for backend and full-stack developers working with Firebase to build scalable cloud applications.

1

Create Firestore collection and add a user with auto-generated ID

Write code to add a user document to the users collection with fields name set to "Alice" and age set to 30. Use Firestore's auto-generated document ID feature by calling add() on the collection reference.

Firebase

import { getFirestore, collection } from 'firebase/firestore';

const db = getFirestore();
const usersCollection = collection(db, 'users');

// Add a user with auto-generated ID
// Your code here

Need a hint?

Use addDoc() with the collection reference and an object for the user data.

2

Add a user document with a custom string ID

Write code to add a user document to the users collection with document ID "user_bob". The user data should have name set to "Bob" and age set to 25. Use the setDoc() function with a document reference created by doc().

Firebase

import { getFirestore, collection, addDoc, doc, setDoc } from 'firebase/firestore';

const db = getFirestore();
const usersCollection = collection(db, 'users');

addDoc(usersCollection, { name: 'Alice', age: 30 });

// Add a user with custom ID 'user_bob'
// Your code here

Need a hint?

Create a document reference with doc() using the collection name and custom ID, then use setDoc() to add data.

3

Add a user document using the user's email as the document ID

Write code to add a user document to the users collection with document ID set to the user's email "[e-mail]". The user data should have name set to "Carol" and age set to 28. Use doc() and setDoc() functions.

Firebase

import { getFirestore, collection, addDoc, doc, setDoc } from 'firebase/firestore';

const db = getFirestore();
const usersCollection = collection(db, 'users');

addDoc(usersCollection, { name: 'Alice', age: 30 });

const bobDoc = doc(db, 'users', 'user_bob');
setDoc(bobDoc, { name: 'Bob', age: 25 });

// Add a user with email as document ID '[e-mail]'
// Your code here

Need a hint?

Use the email string as the document ID by passing it to doc(), then add data with setDoc().

4

Complete Firestore document ID strategies example

Ensure the code includes all three user additions: one with auto-generated ID for Alice, one with custom ID "user_bob" for Bob, and one with email ID "[e-mail]" for Carol. The code should import all necessary Firestore functions and initialize the Firestore database.

Firebase

import { getFirestore, collection, addDoc, doc, setDoc } from 'firebase/firestore';

const db = getFirestore();
const usersCollection = collection(db, 'users');

addDoc(usersCollection, { name: 'Alice', age: 30 });

const bobDoc = doc(db, 'users', 'user_bob');
setDoc(bobDoc, { name: 'Bob', age: 25 });

const carolDoc = doc(db, 'users', '[e-mail]');
setDoc(carolDoc, { name: 'Carol', age: 28 });

// Finalize the Firestore document ID strategies example
// Your code here

Need a hint?

Make sure all previous steps are combined and all imports and variables are included.