Migrating from Realtime Database to Firestore in Firebase - Mini Project: Build & Apply

Migrating from Realtime Database to Firestore

📖 Scenario: You have a Firebase Realtime Database storing user profiles. You want to move this data to Firestore for better querying and scalability.

🎯 Goal: Build a simple Firebase script that reads user data from Realtime Database and writes it into Firestore with the same structure.

📋 What You'll Learn

Create a reference to the Realtime Database users node

Create a Firestore collection reference for users

Read all user data from Realtime Database

Write each user document into Firestore

💡 Why This Matters

🌍 Real World

Many Firebase projects start with Realtime Database and later migrate to Firestore for advanced querying and scalability.

💼 Career

Understanding how to migrate data between Firebase databases is useful for cloud engineers and developers working with Firebase backend services.

1

Setup Firebase Realtime Database reference

Create a variable called rtdbRef that references the path 'users' in the Firebase Realtime Database using firebase.database().ref('users').

Firebase

# Create a variable called rtdbRef referencing 'users' in Realtime Database
# Your code here

Need a hint?

Use firebase.database().ref('users') to get the reference.

2

Setup Firestore collection reference

Create a variable called firestoreUsers that references the 'users' collection in Firestore using firebase.firestore().collection('users').

Firebase

const rtdbRef = firebase.database().ref('users');
# Create a variable called firestoreUsers referencing 'users' collection in Firestore
# Your code here

Need a hint?

Use firebase.firestore().collection('users') to get the Firestore collection reference.

3

Read data from Realtime Database and prepare for migration

Use rtdbRef.once('value') to read all user data from Realtime Database. Inside the callback, get the snapshot value into a variable called usersData.

Firebase

const rtdbRef = firebase.database().ref('users');
const firestoreUsers = firebase.firestore().collection('users');

// Read all users data from Realtime Database
# Your code here

Need a hint?

Use once('value') and snapshot.val() to get the data.

4

Write each user to Firestore

Inside the rtdbRef.once('value').then() callback, use a for...in loop with variable userId to iterate over usersData. For each userId, write the user data to Firestore using firestoreUsers.doc(userId).set(usersData[userId]).

Firebase

const rtdbRef = firebase.database().ref('users');
const firestoreUsers = firebase.firestore().collection('users');

rtdbRef.once('value').then(snapshot => {
  const usersData = snapshot.val();
  // Loop over usersData and write each user to Firestore
  # Your code here
});

Need a hint?

Use a for...in loop and firestoreUsers.doc(userId).set() to write data.