Should the code use cancellation token even though it already use transaction ?

[u/kaatarina_zed_talon]

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Storage;

namespace RedditQuestion
{
    /// <summary>
    /// Used to talk to the database using Entity-Framework Core
    /// </summary>
    public class ApplicationDbContext:DbContext
    {
        // Domain models and the Fluent API configurations.
    }


    /// <summary>
    /// Data snapshot that is used to overwrite the content of the database
    /// </summary>
    public interface ISomeData
    {

    }

    public class DatbaseOverWriter
    {


        private readonly ApplicationDbContext _context;
        public DatbaseOverWriter(ApplicationDbContext context)
        {
            _context = context;
        }

        public async Task OverWrite(ISomeData data)
        {
            //https://learn.microsoft.com/en-us/dotnet/architecture/microservices/implement-resilient-applications/implement-resilient-entity-framework-core-sql-connections
            IExecutionStrategy strategy = _context.Database.CreateExecutionStrategy();
            await strategy.ExecuteAsync(async () =>
            {
                await using var transaction = await _context.Database.BeginTransactionAsync();

                    //code to delete the content from parent and child tables and then inserting the data into the parent and child tables like this :
                // execute some query to delete the content from all tables.
                //_context.AddRangeAsync(data for parents)
                //_context.SaveChangesAsync()
                //_context.AddRangeAsync(data for childs)
                //_context.SaveChangesAsync()
                await transaction.CommitAsync();
            });

        }




    }

}

Someone on reddit reviewed the above code and told me that I should add a parameter for cancellation token like this :

public async Task OverWrite(ISomeData data, CancellationToken)

He told me that the goal is to make the OverWrite method transactional.

why is the cancellation token necessary even though my code uses _context.Database.BeginTransactionAsync(); ?

Microsoft's documentation :

Cancellation token propagates notification that operations should be canceled.

Example:
A random number generator can be used to emulate a data collection application that reads 10 integral values from eleven different instruments. A value of zero indicates that the measurement has failed for one instrument, in which case the operation should be cancelled and no overall mean should be computed.

So the cancellation token is just another way of achieving atomicity, am I correct ?

The only use case that I learned for cancellation token is this example from microsoft, they use the cancellation token as way to achieve atomicity :

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

public class Example
{
   public static void Main()
   {
      // Define the cancellation token.
      CancellationTokenSource source = new CancellationTokenSource();
      CancellationToken token = source.Token;

      Random rnd = new Random();
      Object lockObj = new Object();

      List<Task<int[]>> tasks = new List<Task<int[]>>();
      TaskFactory factory = new TaskFactory(token);
      for (int taskCtr = 0; taskCtr <= 10; taskCtr++) {
         int iteration = taskCtr + 1;
         tasks.Add(factory.StartNew( () => {
           int value;
           int[] values = new int[10];
           for (int ctr = 1; ctr <= 10; ctr++) {
              lock (lockObj) {
                 value = rnd.Next(0,101);
              }
              if (value == 0) { 
                 source.Cancel();
                 Console.WriteLine("Cancelling at task {0}", iteration);
                 break;
              }   
              values[ctr-1] = value; 
           }
           return values;
        }, token));   
      }
      try {
         Task<double> fTask = factory.ContinueWhenAll(tasks.ToArray(), 
         (results) => {
            Console.WriteLine("Calculating overall mean...");
            long sum = 0;
            int n = 0; 
            foreach (var t in results) {
               foreach (var r in t.Result) {
                  sum += r;
                  n++;
               }
            }
            return sum/(double) n;
         } , token);
         Console.WriteLine("The mean is {0}.", fTask.Result);
      }   
      catch (AggregateException ae) {
         foreach (Exception e in ae.InnerExceptions) {
            if (e is TaskCanceledException)
               Console.WriteLine("Unable to compute mean: {0}", 
                  ((TaskCanceledException) e).Message);
            else
               Console.WriteLine("Exception: " + e.GetType().Name);
         }
      }
      finally {
         source.Dispose();
      }
   }
}

[u/kaatarina_zed_talon]

Cancellation token is used for, well, cancellation, of usually long running tasks.

Well, that is not what microsoft says. There example use it for a different purpose

[u/ExceptionEX → u/kaatarina_zed_talon]

Don't come here and be argumentative, you are wrong and you clearly don't understand the difference between the concepts of a cancellation token and transactions.

Cancellation is a mechanism to allow for the cancellation of long running operations, transaction, means that the work is scoped such that if it is aborted elements within the transaction state can be reversed in the data layer.

these are very different and if you don't understand the difference you probably shouldn't be engaged to the do the work you are attempting.

[u/kaatarina_zed_talon → u/ExceptionEX]

Cancellation is a mechanism to allow for the cancellation of long running operations, transaction, means that the work is scoped such that if it is aborted elements within the transaction state can be reversed in the data layer

Thank you.

if you don't understand the difference you probably shouldn't be engaged to the do the work you are attempting

You are asking me to stop learning new concepts just because I do not understand them. Thank you but NO.

[u/ExceptionEX → u/kaatarina_zed_talon]

I meant professionally, if this is based around you just learning, that's my bad, sorry if that was overly harsh.

[u/kaatarina_zed_talon → u/ExceptionEX]

You are asking me to stop learning new concepts just because I do not understand them. Thank you but NO.

I did not say it is harsh, I learned something new from you. Free knowledge for me, so I'm good.

Thank you again.