Service : Service shouldn't have an SQL Transaction

Medium

---

DDD

Service shouldn't have an SQL Transaction.

Using a technical object like a SQL a transaction is a bad smell. SQL transaction should be in a repository.

Classes which names ends Serviceshould not have any variable or method variable/parameters types which contains "SQL", "sql", or "BeginTransaction".

Examples

Example 1:

Negative

Incorrect implementation that violates the practice.

using Microsoft.Data.SqlClient;

namespace Practices.DDD.Service.SQLTransaction
{
    public class OrderService
    {
        private readonly OrderRepository _orderRepository;

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

        public void UpdateData(Order order)
        {
            //Having SQL References in a service is bad smell
            using (var connection = new SqlConnection())
            {
                //Having Database Transaction is a red flag
                using (var transac = connection.BeginTransaction())
                {
                    //Process Order
                    _orderRepository.UpdateData(order, transac);
                    //Process Order with a second method
                    _orderRepository.UpdateLastUpdate(order, transac);
                }
            }
        }

        public void UpdateDataAndLastUpdate(Order order)
        {
            //Process Order
            _orderRepository.UpdateDataAndLastUpdate(order);
        }

    }
}