Pattern Review

Generic Repository Pattern Analysis

Analyze data access code as a senior software engineer with expertise in ORM frameworks and repository design.

Input Required

• Existing data access code (controllers, services, direct database calls)
• Current repository implementations (if any)
• Entity/Model definitions
• Tech stack context (ORM, database, framework)

Analysis Framework

1. Anti-Pattern Detection

Direct ORM/Database Coupling:

• DbContext/session injected directly into controllers
• Raw SQL scattered across business logic
• Query logic duplicated across services
• No abstraction between domain and persistence

Repository Smells:

• Copy-pasted CRUD methods per entity
• Inconsistent method signatures
• Missing common operations (bulk, exists, pagination)
• IQueryable returned leaking ORM details

Testability Issues:

• Data access requiring real database for tests
• Missing interfaces preventing mocks
• Tight coupling forcing integration tests only

2. Repository Design Evaluation

Interface Design:

• Generic constraints (class, entity base)
• Balance generic vs type-safe operations
• Async/sync coverage
• Expression-based filtering

Common Operations Checklist:

• GetById, GetAll, Find (with predicate)
• Add, AddRange
• Update, UpdateRange
• Delete, DeleteRange
• Exists, Count
• Pagination support
• Include/eager loading strategy

Unit of Work Integration:

• Transaction boundary management
• Multiple repository coordination
• SaveChanges responsibility
• Connection lifetime handling

Output Format

Current State Assessment

**Data Access Pattern:** [Direct ORM | Specific Repositories | Hybrid | None]
**Entities Requiring Access:** List discovered entities
**Duplication Analysis:** Quantify repeated CRUD patterns

Priority 1: Core Generic Repository Design

# Proposed IGenericRepository interface
class IGenericRepository(Generic[T]):
    def get_by_id(self, id: int) -> Optional[T]: ...
    def get_all(self) -> List[T]: ...
    def find(self, predicate: Callable[[T], bool]) -> List[T]: ...
    def add(self, entity: T) -> T: ...
    def update(self, entity: T) -> T: ...
    def delete(self, entity: T) -> None: ...
    def exists(self, id: int) -> bool: ...

Priority 2: Unit of Work Integration

Priority 3: Entity-Specific Extensions

Priority 4: Migration Path

Phase 1: Introduce interfaces (non-breaking) Phase 2: Migrate service layer Phase 3: Remove direct DB dependencies Phase 4: Add specification pattern (optional)

Testing Strategy

Show how to test services with mocked repositories.

Design Principles

• Don't expose IQueryable - prevents leaky abstraction
• Keep it simple - avoid over-engineering
• Consider your ORM - EF Core vs Dapper need different approaches
• Respect boundaries - repositories return domain objects, not DTOs
• Plan for custom queries - generic doesn't mean inflexible

What to Avoid

• Overly abstract designs obscuring simple operations
• Ignoring ORM strengths and idioms
• Patterns that hurt query performance
• Unused repository methods
• Forcing async when provider doesn't benefit