Is Realm better than SQLite for mobile apps?

Realm often outperforms SQLite in read/write speeds due to its zero-copy architecture and object-oriented model, making it ideal for complex data. However, SQLite might be preferable for apps needing strict SQL compliance or smaller footprints.

How to set up Realm in a React Native project?

Install the Realm package via npm or yarn, then follow platform-specific linking instructions in the README, such as running pod install for iOS and updating Gradle for Android. Additional configuration may be needed for sync or advanced features.

Can Realm be used for web development?

Realm is primarily designed for mobile devices and not optimized for web browsers. For web apps, consider alternatives like IndexedDB or server-side databases, as Realm's architecture focuses on native mobile performance.

What are the costs for Realm Sync?

Realm offers a free tier with basic sync limits, but higher usage or enterprise features require paid plans. Check Realm's official pricing for details on data transfer, user counts, and support levels.

Realm vs Firebase for mobile databases?

Realm excels in local data persistence and performance with offline-first capabilities, while Firebase provides a full backend-as-a-service with real-time database, auth, and cloud functions. Choose Realm for complex local storage; Firebase for integrated backend solutions.

How to handle data migrations in Realm?

Define migration logic in code by incrementing schema versions and using migration blocks to transform data. The README outlines steps to handle object model changes, but it can be error-prone for large schemas.

Open-Awesome

realm-js

Apache-2.0TypeScriptrealm-react-v0.20.0

A mobile database that runs directly inside phones, tablets, or wearables as an alternative to SQLite and key-value stores.

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6.0k stars612 forks0 contributors

What is realm-js?

Realm is a mobile database that runs directly on devices like phones, tablets, and wearables, providing local data persistence for mobile applications. It serves as an alternative to SQLite and key-value stores with better performance and an object-oriented data model. The database eliminates the need for ORM layers by allowing developers to work with live objects directly.

Target Audience

Mobile developers building iOS, Android, or cross-platform applications that require efficient local data storage, real-time synchronization, or offline capabilities.

Value Proposition

Developers choose Realm for its superior performance compared to SQLite, intuitive object-oriented API that reduces boilerplate code, and built-in real-time sync capabilities for collaborative applications.

Overview

Realm is a mobile database: an alternative to SQLite & key-value stores

Use Cases

Best For

Building mobile apps with complex local data persistence needs
Creating offline-first applications that work without network connectivity
Developing real-time collaborative features in mobile apps
Replacing SQLite with a more performant and developer-friendly alternative
Cross-platform mobile development with consistent data layer APIs
Applications requiring type-safe database queries with compile-time checking

Not Ideal For

Projects primarily targeting web or desktop platforms, as Realm is optimized for mobile devices and may lack server-side features.
Applications that rely heavily on complex SQL queries and stored procedures, since Realm uses a different object-oriented query language.
Teams seeking a completely open-source solution without proprietary dependencies, especially for sync features tied to Realm's cloud services.
Simple apps with trivial data storage needs that could be handled by platform-native storage like SharedPreferences or UserDefaults.

Pros & Cons

Pros

Object-Oriented Simplicity

Stores data as live objects with relationships, eliminating the need for ORM layers and reducing boilerplate code, as highlighted in the README.

Zero-Copy Performance

Uses memory-mapped architecture for fast data access without serialization overhead, offering better performance than SQLite for many use cases.

Built-in Real-time Sync

Provides synchronization capabilities out-of-the-box for enabling collaborative and offline-first applications, as noted in the features.

Cross-Platform Consistency

Works across iOS, Android, and other mobile platforms with consistent APIs, simplifying cross-platform development efforts.

Type-Safe Queries

Features an expressive query language with compile-time type checking for safer data access, reducing runtime errors.

Cons

Sync Service Dependency

Real-time sync capabilities may require using Realm's cloud services, leading to vendor lock-in and potential costs not mentioned as flexible in the README.

Paradigm Shift Required

Developers accustomed to SQL-based databases face a learning curve with the object-oriented model, which the README acknowledges as a departure from traditional approaches.

App Size Overhead

Including Realm can increase application bundle size compared to lighter alternatives like SQLite, a trade-off for its feature set.

Migration Complexities

Schema changes require careful handling with migration blocks, and the README may indicate limitations in tooling for seamless updates.

Open Source Alternative To

realm-js is an open-source alternative to the following products:

Room

Room is an Android persistence library that provides an abstraction layer over SQLite to allow for more robust database access while harnessing the full power of SQLite.

Core Data

Core Data is an Apple framework for managing object graphs and persisting data in macOS, iOS, watchOS, and tvOS applications.

SQLite

Frequently Asked Questions

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