Generic IRepository<T> anti-pattern, specification pattern.

Repository Pattern in .NET — When It Helps vs Hurts

The Repository pattern abstracts data access behind an interface. Generic IRepository<T> over EF Core is usually an anti-pattern: it wraps a unit-of-work (DbContext) in another unit-of-work and leaks IQueryable anyway. Domain repositories (IOrderRepository with business-meaningful queries) earn their keep by hiding persistence complexity. The Specification pattern adds composable query logic without proliferating method overloads.

Interactive Pipeline Flow

FoundationCore LogicProduction

🏛️ Domain — aggregate root

Repositories belong to the domain layer. Only aggregate roots get repositories — not every entity. OrderRepository, not OrderItemRepository.

Architecture Diagrams

Composing specifications for flexible, testable queries.

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Key Design Decisions

🚫Skip generic IRepository<T> over EF Core

DbContext IS the unit of work. DbSet<T> IS the repository. Adding IRepository<T, TId> wraps a UoW in a UoW and leaks IQueryable.

📋Domain repositories for aggregate roots only

IOrderRepository.GetPendingForWarehouse(id) is valuable. IOrderItemRepository is not — access items through the Order aggregate.

📐Specifications over method explosion

Avoid GetByStatus, GetByCustomer, GetByStatusAndCustomer, etc. One Find(ISpecification<Order>) method handles all compositions.

Discussion