Design Patterns & Practices  

Unit of Work Design Pattern with EF Core

Unit of Work Pattern in Entity Framework Core

The Unit of Work (UoW) pattern combines multiple operations—such as inserts, updates, and deletes—into a single transaction. This approach ensures that all changes are committed in a single transaction, preserving data consistency and preventing partial updates. In Entity Framework Core (EF Core), the DbContext serves as a unit of work, tracking entity changes and persisting them within a single transaction. Nevertheless, implementing the pattern explicitly can enhance abstraction, improve testability, and promote a clear separation of concerns.

Key Responsibilities of UoW

  • Tracks changes to entities

  • Coordinates repositories

  • Manages database transactions

  • Commits or rolls back changes

Implementing the Unit of Work pattern alongside the Repository pattern in Entity Framework Core (EF Core) provides a structured, maintainable way to handle database operations. This combination helps organize data access logic, centralize transaction management, and ensure that multiple operations are treated as a single logical unit.

When working with complex business processes, you often need to perform several operations—such as creating, updating, or deleting entities—within the same workflow. The Unit of Work coordinates these operations and commits them as a single transaction, ensuring that either all changes succeed or none are applied. This prevents data inconsistencies caused by partial updates.

At the same time, the Repository pattern abstracts the data access layer by encapsulating queries and CRUD operations for specific entities. Instead of scattering database logic across the application, repositories provide a clean interface for interacting with the data model. The Unit of Work then acts as a central coordinator, managing these repositories and controlling when changes are persisted. In EF Core, although DbContext already behaves like a Unit of Work by tracking changes and saving them together, explicitly implementing these patterns offers additional advantages such as centralized transaction handling and error management, clear separation of concerns between business logic and data access, and many more.

When implementing the Unit of Work alongside the Repository pattern, ensure that individual repository methods do not call the context.SaveChanges(). Instead, all changes should be committed centrally through the Unit of Work to maintain proper transaction control and consistency.

IUnitOfWork Interface

public interface IUnitOfWork : IDisposable
{
    IRepository<Order> Orders { get; }
    IRepository<OrderItem> OrderItems { get; }

    Task<int> SaveChangesAsync();
}

UnitOfWork Implementation

public class UnitOfWork : IUnitOfWork
{
    private readonly ApplicationDbContext _context;

    public IRepository<Order> Orders { get; }
    public IRepository<OrderItem> OrderItems { get; }

    public UnitOfWork(ApplicationDbContext context)
    {
        _context = context;

        Orders = new Repository<Order>(_context);
        OrderItems = new Repository<OrderItem>(_context);
    }

    public async Task<int> SaveChangesAsync()
        => await _context.SaveChangesAsync();

    public void Dispose()
        => _context.Dispose();
}

OrderService Example

public class OrderService
{
    private readonly IUnitOfWork _unitOfWork;

    public OrderService(IUnitOfWork unitOfWork)
    {
        _unitOfWork = unitOfWork;
    }

    public async Task CreateOrderAsync()
    {
        var order = new Order
        {
            OrderDate = DateTime.UtcNow
        };

        await _unitOfWork.Orders.AddAsync(order);

        var item = new OrderItem
        {
            ProductName = "Laptop",
            Quantity = 1,
            Order = order
        };

        await _unitOfWork.OrderItems.AddAsync(item);

        // Single commit point
        await _unitOfWork.SaveChangesAsync();
    }
}

Advantages of the Unit of Work Pattern

  • Ensures consistency across transactions

  • Provides a single, centralized commit mechanism

  • Simplifies and streamlines the service layer

  • Enhances testability (e.g., by mocking IUnitOfWork)

  • Integrates smoothly with Clean Architecture principles

Drawbacks of the Unit of Work Pattern

  • Introduces an additional abstraction layer on top of DbContext

  • Can add unnecessary complexity in certain scenarios

  • May be redundant since DbContext already embodies Unit of Work behavior

When to Use the Unit of Work Pattern

Use a custom Unit of Work in scenarios such as:

  • Following Clean Architecture principles where separation of concerns is key

  • Needing an abstraction layer to decouple database operations from business logic

  • Handling multiple repositories within a single transaction to ensure consistency

  • Improving testability, for example by mocking IUnitOfWork in unit tests

Avoid implementing Unit of Work when:

  • The project is small and doesn’t require extra architectural layers

  • You’re directly working with DbContext in services without additional complexity

  • Abstraction provides no practical benefit and only adds overhead

This way, the guideline is straightforward: Unit of Work is valuable in complex, layered systems but unnecessary in simple applications or when EF Core’s DbContext already covers the needed functionality.

Conclusion

Unit of Work can sharpen transaction management and boost testability in complex, Clean Architecture systems—but don’t add it just for the sake of it. DbContext already does the job, so in simple CRUD apps, keep it lean and stick with what’s built in.

Rule of thumb: Use Unit of Work when complexity demands it; skip it when simplicity ser

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