EF Core 9 : the database operation was expected to affect 1 row(s), but actually affected 0 row(s)

[Arman-Espiar]

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I am using DDD architecture and the following code changes the aggregate root (basically adds a comment which is an entity to the aggregate root).

public sealed class AddCommentToPostCommandHandlers : ICommandHandler<AddCommentToPostCommand, Guid>
{
	private readonly IPostCommandRepository _postRepository;
	private readonly ILogger<AddCommentToPostCommandHandlers> _logger;

	public AddCommentToPostCommandHandlers(IPostCommandRepository postRepository, ILogger<AddCommentToPostCommandHandlers> logger)
	{
		_postRepository = postRepository;
		_logger = logger;
	}

	public async Task<Result<Guid>> Handle(AddCommentToPostCommand request, CancellationToken cancellationToken)
	{
		var post = await _postRepository.GetGraphByAsync(request.PostId, cancellationToken);

		if (post is not null)
		{
			post.AddComment(request.DisplayName, request.Email, request.CommentText);

			if (post.Result.IsSuccess)
			{
				_postRepository.UpdateBy(post);

				await _postRepository.CommitAsync(cancellationToken);

				return post.Id;
			}

			return post.Result;
		}

		return Result.Fail(ErrorMessages.NotFound(request.ToString()));
	}
}

This code worked fine with EF Core 8, but when I upgraded to EF Core 9, I get the following error:

Microsoft.EntityFrameworkCore.DbUpdateConcurrencyException: The
database operation was expected to affect 1 row(s), but actually
affected 0 row(s); data may have been modified or deleted since
entities were loaded.

This error also occurs when editing a comment, whereas in the previous version (EF Core 8) this error did not occur.

Aggregate root code:

namespace ContentService.Core.Domain.Aggregates.Posts;

public class Post : AggregateRoot<Post>
{
	public Title Title { get; private set; }
	public Description Description { get; private set; }

	public Text Text { get; private set; }

	private readonly List<GuidId> _categoryIds;

	public virtual IReadOnlyList<GuidId> CategoryIds => _categoryIds;

	#region بارگذاری تنبل در سطح دامنه

	private List<Comment> _comments;

	public virtual IReadOnlyList<Comment> Comments
	{
		get
		{
			if (_comments == null)
			{
				LoadComments();
			}

			return _comments.AsReadOnly();
		}
	}

	private void LoadComments()
	{
		// Load comments from the data source here.
		// This is just a placeholder. You will need to replace this with your actual data loading logic.

		_comments = new List<Comment>();
	}

	#endregion End بارگذاری تنبل در سطح دامنه

	public Post()
	{
		_categoryIds = new List<GuidId>();
	}

	private Post(string? title, string? description, string? text) : this()
	{
		var titleResult = Title.Create(title);

		Result.WithErrors(titleResult.Errors);

		var descriptionResult = Description.Create(description);

		Result.WithErrors(descriptionResult.Errors);

		var contentResult = Text.Create(text);

		Result.WithErrors(contentResult.Errors);

		if (Result.IsSuccess)
		{
			Title = titleResult.Value;
			Description = descriptionResult.Value;
			Text = contentResult.Value;
		}
	}

	public Post Create(string? title, string? description, string? text)
	{
		var checkValidations = new Post(title, description, text);

		Result.WithErrors(checkValidations.Result.Errors);

		if (Result.IsFailed) 
            return this;

		if (Result.IsSuccess)
		{
			this.Text = checkValidations.Text;
			this.Title = checkValidations.Title;
			this.Description = checkValidations.Description;

			RaiseDomainEvent(new PostCreatedEvent(Id, this.Title.Value, this.Description.Value, this.Text.Value));
		}

		return this;
	}

	public Post UpdatePost(string? title, string? description, string? text)
	{
		var checkValidations = new Post(title, description, text);

		Result.WithErrors(checkValidations.Result.Errors);

		if (Result.IsFailed) 
            return this;

		if (Result.IsSuccess)
		{
			this.Title = checkValidations.Title;
			this.Description = checkValidations.Description;
			this.Text = checkValidations.Text;

			RaiseDomainEvent(new PostUpdatedEvent(Id, Title.Value!, Description.Value!, Text.Value!));

            Result.WithSuccess(SuccessMessages.SuccessUpdate(DataDictionary.Post));
		}

		return this;
	}

	public Post RemovePost(Guid? id)
	{
		var guidResult = GuidId.Create(id);

		if (guidResult.IsFailed)
		{
			Result.WithErrors(guidResult.Errors);
			return this;
		}

		// Note: if have IsDeleted property (soft delete) we can change to true here
		RaiseDomainEvent(new PostRemovedEvent(id));

		Result.WithSuccess(SuccessMessages.SuccessDelete(DataDictionary.Post));

		return this;
	}

	#region Category

	public Post AddCategory(Guid? categoryId)
	{
		var guidResult = GuidId.Create(categoryId);

		if (guidResult.IsFailed)
		{
			Result.WithErrors(guidResult.Errors);
			return this;
		}

		if (!_categoryIds.Contains(guidResult.Value))       //جلوگیری از تکراری بودن دسته بندی	
		{
			_categoryIds.Add(guidResult.Value);

			RaiseDomainEvent(new PostCategoryAddedEvent(Id, (Guid)categoryId!));
		}

		return this;
	}

	public Post ChangeCategory(Guid? oldCategoryId, Guid? newCategoryId)
	{
		var oldGuidResult = GuidId.Create(oldCategoryId);
		var newGuidResult = GuidId.Create(newCategoryId);

		if (oldGuidResult.IsFailed)
		{
			Result.WithErrors(oldGuidResult.Errors);
			return this;
		}

		if (newGuidResult.IsFailed)
		{
			Result.WithErrors(newGuidResult.Errors);
			return this;
		}

		if (_categoryIds.Contains(oldGuidResult.Value))
		{
			var indexOldCategory = _categoryIds.IndexOf(oldGuidResult.Value);

			if (!_categoryIds.Contains(newGuidResult.Value))
			{
				_categoryIds.RemoveAt(indexOldCategory);
				_categoryIds.Insert(indexOldCategory, newGuidResult.Value);
			}
			else
			{
				_categoryIds.RemoveAt(indexOldCategory);
			}

			RaiseDomainEvent(new CategoryPostChangedEvent(Id, (Guid)oldCategoryId!, (Guid)newCategoryId!));
		}
		else
		{
			Result.WithError(ErrorMessages.NotFound(DataDictionary.Category));
		}

		return this;
	}

	public Post RemoveCategory(Guid? categoryId)
	{
		var guidResult = GuidId.Create(categoryId);

		if (guidResult.IsFailed)
		{
			Result.WithErrors(guidResult.Errors);
			return this;
		}

		if (_categoryIds.Contains(guidResult.Value))
		{
			_categoryIds.Remove(guidResult.Value);

			RaiseDomainEvent(new CategoryPostRemovedEvent(Id, (Guid)categoryId!));
		}

		return this;
	}

	#endregion End Category

	#region Comments

	public Post AddComment(string? name, string? email, string? text)

	{

		var commentResult = Comment.Create(this, name, email, text);

		Result.WithErrors(commentResult.Errors);

		if (Result.IsFailed)

		{

			return this;

		}

		var hasAny = Comments

			.Any(c => c.Name == commentResult.Value.Name

					  && c.Email == commentResult.Value.Email

					  && c.CommentText == commentResult.Value.CommentText);

		if (hasAny)

		{

			var errorMessage = ValidationMessages.Repetitive(DataDictionary.Comment);

			Result.WithError(errorMessage);

			return this;

		}

		_comments.Add(commentResult.Value);

		RaiseDomainEvent(new CommentAddedEvent(this.Id, commentResult.Value.Id, commentResult.Value.Name.Value, commentResult.Value.Email.Value, commentResult.Value.CommentText.Value));

		return this;

	}

	public Post ChangeCommentText(string? name, string? email, string? text, string? newText)

	{

		var commentOldResult = Comment.Create(this, name, email, text);

		var commentNewResult = Comment.Create(this, name, email, newText);

		Result.WithErrors(commentOldResult.Errors);

		Result.WithErrors(commentNewResult.Errors);

		var emailGuardResult = Guard.CheckIf(commentNewResult.Value.Email, DataDictionary.Email)

			.Equal(commentOldResult.Value.Email);

		Result.WithErrors(emailGuardResult.Errors);

		var nameGuardResult = Guard.CheckIf(commentNewResult.Value.Name, DataDictionary.Name)

			.Equal(commentOldResult.Value.Name);

		Result.WithErrors(nameGuardResult.Errors);

		var commentTextGuardResult = Guard.CheckIf(commentNewResult.Value.CommentText, DataDictionary.CommentText)

			.NotEqual(commentOldResult.Value.CommentText);

		Result.WithErrors(commentTextGuardResult.Errors);

		if (Result.IsFailed)

		{

			return this;

		}

		LoadComments();

		var hasAny = Comments

			.Any(c => c.Name == commentNewResult.Value.Name

					  && c.Email == commentNewResult.Value.Email

					  && c.CommentText == commentNewResult.Value.CommentText);

		if (hasAny)

		{

			var errorMessage = ValidationMessages.Repetitive(DataDictionary.Comment);

			Result.WithError(errorMessage);

			return this;

		}

		//var commentIndex = _comments

		//	.FindIndex(c => c.Name == commentOldResult.Value.Name

		//			  && c.Email == commentOldResult.Value.Email

		//			  && c.CommentText == commentOldResult.Value.CommentText);

		var commentIndex = Comments

			.Select((c, i) => new { Comment = c, Index = i })

			.FirstOrDefault(x => x.Comment.Name == commentOldResult.Value.Name

								 && x.Comment.Email == commentOldResult.Value.Email

								 && x.Comment.CommentText == commentOldResult.Value.CommentText)?.Index;

		if (commentIndex >= 0)

		{

			_comments.RemoveAt((int)commentIndex);

			_comments.Insert((int)commentIndex, commentNewResult.Value);

			RaiseDomainEvent(new CommentEditedEvent(this.Id, commentNewResult.Value.Id, commentNewResult.Value.Name.Value, commentNewResult.Value.Email.Value, commentNewResult.Value.CommentText.Value));

		}

		return this;

	}

	public Post RemoveComment(string? name, string? email, string? text)

	{

		var commentResult = Comment.Create(this, name, email, text);

		Result.WithErrors(commentResult.Errors);

		if (Result.IsFailed)

		{

			return this;

		}

		var commentFounded = Comments

			.FirstOrDefault(c => c.Name?.Value?.ToLower() == commentResult.Value.Name?.Value?.ToLower()

								 && c.Email?.Value?.ToLower() == commentResult.Value?.Email?.Value?.ToLower()

								 && c.CommentText.Value?.ToLower() == commentResult?.Value?.CommentText.Value?.ToLower());

		if (commentFounded is null)

		{

			var errorMessage = ErrorMessages.NotFound(DataDictionary.Comment);

			Result.WithError(errorMessage);

			return this;

		}

		_comments.Remove(commentFounded);

		Result.WithSuccess(SuccessMessages.SuccessDelete(DataDictionary.Comment));

		RaiseDomainEvent(new CommentRemovedEvent(Id, name, email, text));

		return this;

	}

	#endregion

}

and comment entity is:

namespace ContentService.Core.Domain.Aggregates.Posts.Entities;

public class Comment : Entity

{

	public DisplayName Name { get; private set; }

	public Email Email { get; private set; }

	public CommentText CommentText { get; private set; }

	public Guid PostId { get; private set; }

	private Comment()

	{

	}

	private Comment(Guid postId, DisplayName name, Email email, CommentText text) : this()

	{

		PostId = postId;

		Name = name;

		Email = email;

		CommentText = text;

	}

	public static Result<Comment> Create(Guid? postId, string? name, string? email, string? text)

	{

		Result<Comment> result = new();

		if (!postId.HasValue || postId == Guid.Empty)

		{

			var errorMessage = ValidationMessages.Required(DataDictionary.Post);

			result.WithError(errorMessage);

		}

		var displayNameResult = DisplayName.Create(name);

		result.WithErrors(displayNameResult.Errors);

		var emailResult = Email.Create(email);

		result.WithErrors(emailResult.Errors);

		var textResult = CommentText.Create(text);

		result.WithErrors(textResult.Errors);

		if (result.IsFailed)

		{

			return result;

		}

		var returnValue = new Comment((Guid)postId!, displayNameResult.Value, emailResult.Value, textResult.Value);

		result.WithValue(returnValue);

		return result;

	}

}

and ef config:

internal sealed class PostConfiguration : IEntityTypeConfiguration<Post>

{

	public void Configure(EntityTypeBuilder<Post> builder)

	{

		builder.Property(p => p.CategoryIds)

			.HasConversion(

				v => string.Join(',', v.Select(c => c.Value)),

				v => v.Split(',', StringSplitOptions.RemoveEmptyEntries).Select(c => GuidId.Create(c).Value).ToList()

			);

		builder.Property(p => p.Title)

			.IsRequired(true)

			.HasMaxLength(Title.Maximum)

			.HasConversion(p => p.Value, p => Title.Create(p).Value);

		builder.Property(p => p.Description)

			.IsRequired(true)

			.HasMaxLength(Description.Maximum)

			.HasConversion(d => d.Value, d => Description.Create(d).Value);

		builder.Property(p => p.Text)

			.IsRequired(true)

			.HasConversion(t => t.Value, t => Text.Create(t).Value);

		builder.OwnsMany<Comment>(c => c.Comments, cc =>

		{

			cc.ToTable("Comments");

			cc.Property(c => c.Email)

				.IsRequired(true)

				.HasConversion(e => e.Value, e => Email.Create(e).Value);

			cc.Property(c => c.Name)

				.IsRequired(true)

				.HasMaxLength(DisplayName.Maximum)

				.HasConversion(e => e.Value, e => DisplayName.Create(e).Value);

			cc.Property(c => c.CommentText)

				.IsRequired(true)

				.HasMaxLength(CommentText.Maximum)

				.HasConversion(e => e.Value, e => CommentText.Create(e).Value);

		});

	}

}

[cincuranet]

This issue is lacking enough information for us to be able to fully understand what is happening. Please attach a small, runnable project or post a small, runnable code listing that reproduces what you are seeing so that we can investigate.

[Arman-Espiar]

This issue is lacking enough information for us to be able to fully understand what is happening. Please attach a small, runnable project or post a small, runnable code listing that reproduces what you are seeing so that we can investigate.

You can download it from this repository. See, I have an aggregate called post which has an entity called Comment which is defined as Owns. The code works correctly and the comment is added to the post, but the state of the post entity remains untracked. Even with the update function or manually changing the state, I still get the same error.

[ajcvickers]

@Arman-Espiar There is a lot of different projects in the code you shared. We typically need to be able to run the code to reproduce what you are seeing. What steps should we take to reproduce the problem with the code you posted?

[Arman-Espiar]

@ajcvickers First run update-database to create the project database. Then run the project and create a post according to CreatePostCommandValidation (which is present in ApplicationService layer) in CreatePost api. Then do the same for Comment, you will face error while creating Comment or changing it (in short working with Comment ).

[ajcvickers]

@Arman-Espiar On which project?

[Arman-Espiar]

@ajcvickers Inside ContentService.Core.Domain the domain logic is in Posts aggregate. Commands are in ContentService.Core.Contracts (Posts aggregate) and CommandHandlers are in ContentService.Core.ApplicationService project (Posts aggregate). EF and database related settings are also in ContentService.Infrastructure.Persistence.Sql.Commands (Posts aggregate) project (Post and Comment are next to each other in each project) and finally Api Controller is in ContentService.Endpoints.API PostController.cs

[Arman-Espiar]

I found the problem. In the definition of Comment (Entity), I had used PostId, which was causing the error (because the entire post, including Comment, is defined as OwnsMany), but here I had given a reference to PostId based on DDD rules.

using ContentService.Core.Domain.Aggregates.Posts.ValueObjects;

using FluentResults;

using MDF.Framework.SeedWork;
using MDF.Resources.Common;
using MDF.Resources.Common.FormattedMessages;

namespace ContentService.Core.Domain.Aggregates.Posts.Entities;
public class Comment : Entity
{
	public DisplayName Name { get; private set; }
	public Email Email { get; private set; }
	public CommentText CommentText { get; private set; }
	public Guid PostId { get; private set; }
	private Comment()
	{

	}
	private Comment(Guid postId, DisplayName name, Email email, CommentText text) : this()
	{
		PostId = postId;
		Name = name;
		Email = email;
		CommentText = text;
	}

	public static Result<Comment> Create(Guid? postId, string? name, string? email, string? text)
	{
		Result<Comment> result = new();

		if (!postId.HasValue || postId == Guid.Empty)
		{
			var errorMessage = ValidationMessages.Required(DataDictionary.Post);
			result.WithError(errorMessage);
		}

		var displayNameResult = DisplayName.Create(name);
		result.WithErrors(displayNameResult.Errors);

		var emailResult = Email.Create(email);
		result.WithErrors(emailResult.Errors);

		var textResult = CommentText.Create(text);
		result.WithErrors(textResult.Errors);

		if (result.IsFailed)
		{
			return result;
		}

		var returnValue = new Comment((Guid)postId!, displayNameResult.Value, emailResult.Value, textResult.Value);
		result.WithValue(returnValue);
		return result;
	}

}

But as I said, Comment is part of Post (the ef settings I had done), I need to give a reference to the Post object itself instead of PostId.

using ContentService.Core.Domain.Aggregates.Posts.ValueObjects;

using FluentResults;

using MDF.Framework.SeedWork;
using MDF.Resources.Common;
using MDF.Resources.Common.FormattedMessages;

namespace ContentService.Core.Domain.Aggregates.Posts.Entities;
public class Comment : Entity
{
	public DisplayName Name { get; private set; }
	public Email Email { get; private set; }
	public CommentText CommentText { get; private set; }
	public Post Post { get; private set; }
	private Comment()
	{

	}
	private Comment(Post post, DisplayName name, Email email, CommentText text) : this()
	{
		Post = post;
		Name = name;
		Email = email;
		CommentText = text;
	}

	public static Result<Comment> Create(Post? post, string? name, string? email, string? text)
	{
		Result<Comment> result = new();

		if (post is null)
		{
			var errorMessage = ValidationMessages.Required(DataDictionary.Post);
			result.WithError(errorMessage);
		}

		var displayNameResult = DisplayName.Create(name);
		result.WithErrors(displayNameResult.Errors);

		var emailResult = Email.Create(email);
		result.WithErrors(emailResult.Errors);

		var textResult = CommentText.Create(text);
		result.WithErrors(textResult.Errors);

		if (result.IsFailed)
		{
			return result;
		}

		var returnValue = new Comment(post!, displayNameResult.Value, emailResult.Value, textResult.Value);
		result.WithValue(returnValue);
		return result;
	}

}