Realm database in React Native - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Realm database in mobile development?

Realm is a mobile database designed for easy and fast data storage on devices. It works offline and syncs data when online.

beginner

How do you define a schema in Realm?

A schema in Realm is a JavaScript object that describes the structure of your data, including properties and their types.

intermediate

What is a Realm transaction?

A Realm transaction is a block of code where you can safely create, update, or delete data. Changes inside a transaction are saved together.

intermediate

How does Realm handle offline data?

Realm stores data locally on the device, allowing apps to work offline. When online, it can sync changes with a server.

intermediate

What is the benefit of using Realm over SQLite in React Native?

Realm offers a simpler API, live objects, reactive data, and better performance without needing complex SQL queries.

What is the first step to use Realm in a React Native app?

A Write SQL queries

B Create a REST API

C Install Redux

D Define a schema for your data

You start by defining a schema that describes your data structure before using Realm.

Which method is used to write data safely in Realm?

A realm.update()

B realm.write()

C realm.commit()

D realm.save()

realm.write() wraps your data changes in a transaction to ensure safety.

How does Realm keep your UI updated with data changes?

A By using live objects that update automatically

B By polling the database every second

C By manual refresh only

D By using Redux only

Realm provides live objects that reflect changes immediately, keeping UI in sync.

What happens if you try to write data outside a Realm transaction?

A An error is thrown

B Data is saved anyway

C Data is lost silently

D Realm automatically creates a transaction

Realm requires all writes inside a transaction; otherwise, it throws an error.

Which of these is NOT a Realm feature?

A Offline data storage

B Live objects and reactive updates

C Automatic SQL query generation

D Data synchronization with server

Realm does not generate SQL queries; it uses its own database engine.

Explain how to define and use a Realm schema in a React Native app.

Think about how you describe your data and then create objects.

Describe the role of transactions in Realm and why they are important.

Consider what happens when you change data and want it saved correctly.