Architecting the Data Layer

Contents

• Core Architecture
• Services Implementation
• Repository Implementation
• Caching Strategies
• Workflows
• Examples

Core Architecture

Construct the data layer as the Single Source of Truth (SSOT) for all application data. In an MVVM architecture, the data layer represents the Model. Never update application data outside of this layer.

Separate the data layer into two distinct components: Repositories and Services.

Repositories

• Act as the SSOT for a specific domain entity.
• Contain business logic for data mutation, polling, caching, and offline synchronization.
• Transform raw data models (API/DB models) into Domain Models (clean data classes containing only what the UI needs).
• Inject Services as private members to prevent the UI layer from bypassing the repository.

Services

• Act as stateless wrappers around external data sources (HTTP clients, SQLite databases, platform plugins).
• Perform no business logic or data transformation beyond basic JSON serialization.