What is Monolithic Architecture

Monolithic architecture is a traditional software design pattern where the entire application is built as a single unit.

Key Characteristics

• Single Codebase
• Tightly Coupled Components
• Single Deployment Unit
• Centralized Data Management

Example. E-Commerce Application

Consider a basic e-commerce system where users can browse products, add them to a cart, and place orders.

Monolithic Application Code Structure in .NET

// Controller Layer (ASP.NET MVC)
public class OrderController : Controller 
{
    private readonly OrderService _orderService;

    public OrderController(OrderService orderService)
    {
        _orderService = orderService;
    }

    [HttpPost]
    public IActionResult PlaceOrder(Order order)
    {
        _orderService.ProcessOrder(order);
        return Ok("Order placed successfully!");
    }
}

// Service Layer (Business Logic)
public class OrderService 
{
    private readonly OrderRepository _orderRepository;

    public OrderService(OrderRepository orderRepository)
    {
        _orderRepository = orderRepository;
    }

    public void ProcessOrder(Order order)
    {
        _orderRepository.SaveOrder(order);
    }
}

// Data Access Layer (Database Interaction)
public class OrderRepository 
{
    private readonly ApplicationDbContext _context;

    public OrderRepository(ApplicationDbContext context)
    {
        _context = context;
    }

    public void SaveOrder(Order order)
    {
        _context.Orders.Add(order);
        _context.SaveChanges();
    }
}

Advantages

• Easy to Develop
• Single Deployment
• Better Performance
• Easier Debugging

Disadvantages

• Difficult to Scale
• Hard to Maintain
• Slow Deployment
• Technology Lock-in

Comparison: Monolithic vs Microservices

Conclusion

Monolithic architecture is easy to start with and works well for small applications. However, as applications grow, scaling and maintaining a monolithic system becomes a challenge.