firebase-database

# Firebase Realtime Database Skill This skill defines how to correctly implement Firebase Realtime Database in Flutter applications, covering data modeling, queries, real-time sync, offline support, and security rules. ## When to Use Use this skill when working with Firebase Realtime Database for **simple data models**, **low-latency sync**, or **presence functionality**. For rich data models requiring complex queries and high scalability, use Cloud Firestore instead. --- ## 1. Database Selection Choose **Realtime Database** when the app needs: - Simple data models with simple lookups. - Extremely low-latency synchronization (typical response times under 10ms). - Deep queries that return an entire subtree by default. - Access to data at any granularity, down to individual leaf-node values. - Frequent state-syncing with built-in presence functionality. Choose **Cloud Firestore** instead for rich data models requiring queryability, scalability, and high availability. --- ## 2. Setup and Configuration ``` flutter pub add firebase_database ``` ```dart import 'package:firebase_database/firebase_database.dart'; // After Firebase.initializeApp(): final DatabaseReference ref = FirebaseDatabase.instance.ref(); ``` - Select the database location closest to users. - Enable persistence for offline capabilities: ```dart FirebaseDatabase.instance.setPersistenceEnabled(true); FirebaseDatabase.instance.setPersistenceCacheSizeBytes(10000000); // 10MB ``` ### Setup Checklist 1....