Repository Pattern

Why?

 Separate business code from data access

1. Separation of concerns
2. Testability

Intent

Encapsulate data access

1. Data appears to live inside an in-memory collection

Demo

Applicability

Anytime you need data persistence

SQL Database

Web service

File system

Consequences

Increased level of abstraction

1. More classes, less duplicated code
2. Maintainability, flexibility, testability

Further away from data

1. Shielded from infrastructure
2. Harder to optimize

Related Patterns

• Unit of Work
• Specification
• Identity Map
• Decorator