C#•9mo ago

DbConcurrencyException, what am I missing?

Hi, getting this on the SaveChangesAsync and im not really sure what im doing wrong.

DbConcurrencyException: 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.

Inside UserService.cs:

 public async Task SetVariable(Guid productId, Guid userId, string requestKey, string requestValue)
    {
        var product = await productRepository.GetByIdAsync(productId);
        if (product is null)
        {
            throw new ProductNotFoundException(productId);
        }

        var user = await userRepository.GetByIdAsync(productId, userId);
        if (user is null)
        {
            throw new UserNotFoundException(userId);
        }

        user.SetVariable(requestKey, requestValue);
        userRepository.Update(user);
        await unitOfWork.SaveChangesAsync();
    }

 public async Task SetVariable(Guid productId, Guid userId, string requestKey, string requestValue)
    {
        var product = await productRepository.GetByIdAsync(productId);
        if (product is null)
        {
            throw new ProductNotFoundException(productId);
        }

        var user = await userRepository.GetByIdAsync(productId, userId);
        if (user is null)
        {
            throw new UserNotFoundException(userId);
        }

        user.SetVariable(requestKey, requestValue);
        userRepository.Update(user);
        await unitOfWork.SaveChangesAsync();
    }

 public async Task SetVariable(Guid productId, Guid userId, string requestKey, string requestValue)
    {
        var product = await productRepository.GetByIdAsync(productId);
        if (product is null)
        {
            throw new ProductNotFoundException(productId);
        }

        var user = await userRepository.GetByIdAsync(productId, userId);
        if (user is null)
        {
            throw new UserNotFoundException(userId);
        }

        user.SetVariable(requestKey, requestValue);
        userRepository.Update(user);
        await unitOfWork.SaveChangesAsync();
    }

 public async Task SetVariable(Guid productId, Guid userId, string requestKey, string requestValue)
    {
        var product = await productRepository.GetByIdAsync(productId);
        if (product is null)
        {
            throw new ProductNotFoundException(productId);
        }

        var user = await userRepository.GetByIdAsync(productId, userId);
        if (user is null)
        {
            throw new UserNotFoundException(userId);
        }

        user.SetVariable(requestKey, requestValue);
        userRepository.Update(user);
        await unitOfWork.SaveChangesAsync();
    }

Inside User.cs:

    public ICollection<UserVariable> Variables { get; set; }

    public void SetVariable(string key, string value)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(key);

        var existingVariable = Variables.FirstOrDefault(v => v.Key.Equals(key, StringComparison.OrdinalIgnoreCase));

        if (existingVariable != null)
        {
            existingVariable.UpdateValue(value);
        }
        else
        {
            var newVariable = UserVariable.Create(Guid.NewGuid(), Id, key, value);
            Variables.Add(newVariable);
        }
    }

    public ICollection<UserVariable> Variables { get; set; }

    public void SetVariable(string key, string value)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(key);

        var existingVariable = Variables.FirstOrDefault(v => v.Key.Equals(key, StringComparison.OrdinalIgnoreCase));

        if (existingVariable != null)
        {
            existingVariable.UpdateValue(value);
        }
        else
        {
            var newVariable = UserVariable.Create(Guid.NewGuid(), Id, key, value);
            Variables.Add(newVariable);
        }
    }

    public ICollection<UserVariable> Variables { get; set; }

    public void SetVariable(string key, string value)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(key);

        var existingVariable = Variables.FirstOrDefault(v => v.Key.Equals(key, StringComparison.OrdinalIgnoreCase));

        if (existingVariable != null)
        {
            existingVariable.UpdateValue(value);
        }
        else
        {
            var newVariable = UserVariable.Create(Guid.NewGuid(), Id, key, value);
            Variables.Add(newVariable);
        }
    }

    public ICollection<UserVariable> Variables { get; set; }

    public void SetVariable(string key, string value)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(key);

        var existingVariable = Variables.FirstOrDefault(v => v.Key.Equals(key, StringComparison.OrdinalIgnoreCase));

        if (existingVariable != null)
        {
            existingVariable.UpdateValue(value);
        }
        else
        {
            var newVariable = UserVariable.Create(Guid.NewGuid(), Id, key, value);
            Variables.Add(newVariable);
        }
    }

Inside UserRepository.cs:

    public void Update(User user)
    {
        dbContext.Set<User>().Update(user);
    }

    public void Update(User user)
    {
        dbContext.Set<User>().Update(user);
    }

    public void Update(User user)
    {
        dbContext.Set<User>().Update(user);
    }

    public void Update(User user)
    {
        dbContext.Set<User>().Update(user);
    }

JuicyOP•4/26/25, 1:51 PM

Also to mention, I do include Variables when getting the user and I also tried without the explicit Update call

Angius•4/26/25, 2:01 PM

I generally avoid using .Update().Update()

Angius•4/26/25, 2:01 PM

And using repositories, but that's another matter

Angius•4/26/25, 2:02 PM

See if using .ExecuteUpdateAsync().ExecuteUpdateAsync() would fix the issue

Jimmacle•4/26/25, 2:09 PM

ah, the joys of wrapping EF in generic repositories

JuicyOP•4/26/25, 2:09 PM

Jimmacle•4/26/25, 2:09 PM

which you shouldn't if you have a choice

JuicyOP•4/26/25, 2:10 PM

Why do "best practices" youtube channels teach this stuff

Jimmacle•4/26/25, 2:10 PM

¯\_(ツ)_/¯

Jimmacle•4/26/25, 2:10 PM

lots of useless content out there

JuicyOP•4/26/25, 2:10 PM

anyway

JuicyOP•4/26/25, 2:10 PM

  dbContext.Set<User>().ExecuteUpdateAsync(
            u => u.SetProperty(x => x.Variables, user.Variables));

  dbContext.Set<User>().ExecuteUpdateAsync(
            u => u.SetProperty(x => x.Variables, user.Variables));

JuicyOP•4/26/25, 2:10 PM

is this how you use it?

JuicyOP•4/26/25, 2:14 PM

It doesnt seem to work

Jimmacle•4/26/25, 2:14 PM

that would set those variables on every single user in the table

Jimmacle•4/26/25, 2:14 PM

you didn't filter it beforehand

JuicyOP•4/26/25, 2:15 PM

Jimmacle•4/26/25, 2:15 PM

i'm not actually sure how executeupdate works with navigation properties, i haven't tried it

JuicyOP•4/26/25, 2:15 PM

is there another possible way I could fix the issue?

Jimmacle•4/26/25, 2:16 PM

as far as options go, you can load, modify, then save the user and let the change tracker deal with it

Jimmacle•4/26/25, 2:16 PM

if you can tolerate the performance penalty of 2 round trips

JuicyOP•4/26/25, 2:16 PM

yeah this isnt very performance dependant

JJimmacle as far as options go, you can load, modify, then save the user and let the chang...

JuicyOP•4/26/25, 2:17 PM

thats kinda what I tried to do I guess

JuicyOP•4/26/25, 2:17 PM

loading the user, modifying it's Variables collection and then trying to save the user

Jimmacle•4/26/25, 2:17 PM

you don't need to use

Update

Update

if the object is already being tracked by the dbcontext

JuicyOP•4/26/25, 2:18 PM

yeah that makes sense

JuicyOP•4/26/25, 2:18 PM

but UserVariable has its own table as well

Jimmacle•4/26/25, 2:18 PM

that's fine, the change tracker can deal with that

JuicyOP•4/26/25, 2:19 PM

But even without the

Update

Update

its giving me the DbUpdateConcurrencyException

JuicyOP•4/26/25, 2:19 PM

It feels like it should work..?

JuicyOP•4/26/25, 2:20 PM

[16:18:59 INF] Executed DbCommand (1ms) [Parameters=[@p3='?' (DbType = Guid), @p0='?' (Size = 64), @p1='?' (DbType = Guid), @p2='?' (Size = 512)], CommandType='Text', CommandTimeout='30']
SET IMPLICIT_TRANSACTIONS OFF;
SET NOCOUNT ON;
UPDATE [UserVariables] SET [Key] = @p0, [UserId] = @p1, [Value] = @p2
OUTPUT 1
WHERE [Id] = @p3;

[16:18:59 INF] Executed DbCommand (1ms) [Parameters=[@p3='?' (DbType = Guid), @p0='?' (Size = 64), @p1='?' (DbType = Guid), @p2='?' (Size = 512)], CommandType='Text', CommandTimeout='30']
SET IMPLICIT_TRANSACTIONS OFF;
SET NOCOUNT ON;
UPDATE [UserVariables] SET [Key] = @p0, [UserId] = @p1, [Value] = @p2
OUTPUT 1
WHERE [Id] = @p3;

Jimmacle•4/26/25, 2:20 PM

are you somehow changing the ID of the user (or variable) either in the entity or in the db in the middle of this happening?

JuicyOP•4/26/25, 2:21 PM

yes the variable is recieving a new ID

JuicyOP•4/26/25, 2:21 PM

   var newVariable = UserVariable.Create(Guid.NewGuid(), Id, key, value);

   var newVariable = UserVariable.Create(Guid.NewGuid(), Id, key, value);

Jimmacle•4/26/25, 2:21 PM

so you need to insert, not update

JuicyOP•4/26/25, 2:21 PM

using System.ComponentModel.DataAnnotations;

namespace Lightning.Domain.Models;

public sealed class UserVariable : BaseEntity
{
    private const int MaxKeyLength = 64;
    private const int MaxValueLength = 256;
    private UserVariable(Guid id, Guid userId, string key, string? value) : base(id)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(key, nameof(key));
        if (key.Length > MaxKeyLength)
        {
            throw new ArgumentException($"Key length exceeds {MaxKeyLength} characters.", nameof(key));
        }
        if (value?.Length > MaxValueLength)
        {
            throw new ArgumentException($"Value length exceeds {MaxValueLength} characters.", nameof(value));
        }
        
        UserId = userId;
        Key = key;
        Value = value;
    }
    

    [MaxLength(MaxKeyLength)] public string Key { get; private set; }
    [MaxLength(MaxValueLength)] public string? Value { get; private set; }
    
    public Guid UserId { get; private set; }
    public User User { get; private set; } = null!;
    
    public static UserVariable Create(Guid id, Guid userId, string key, string? value)
    {
        return new UserVariable(id, userId, key, value);
    }
    
    public void UpdateValue(string? newValue)
    {
        if (newValue?.Length > MaxValueLength)
        {
            throw new ArgumentException($"Value length exceeds {MaxValueLength} characters.", nameof(newValue));
        }
        Value = newValue;
    }
}

using System.ComponentModel.DataAnnotations;

namespace Lightning.Domain.Models;

public sealed class UserVariable : BaseEntity
{
    private const int MaxKeyLength = 64;
    private const int MaxValueLength = 256;
    private UserVariable(Guid id, Guid userId, string key, string? value) : base(id)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(key, nameof(key));
        if (key.Length > MaxKeyLength)
        {
            throw new ArgumentException($"Key length exceeds {MaxKeyLength} characters.", nameof(key));
        }
        if (value?.Length > MaxValueLength)
        {
            throw new ArgumentException($"Value length exceeds {MaxValueLength} characters.", nameof(value));
        }
        
        UserId = userId;
        Key = key;
        Value = value;
    }
    

    [MaxLength(MaxKeyLength)] public string Key { get; private set; }
    [MaxLength(MaxValueLength)] public string? Value { get; private set; }
    
    public Guid UserId { get; private set; }
    public User User { get; private set; } = null!;
    
    public static UserVariable Create(Guid id, Guid userId, string key, string? value)
    {
        return new UserVariable(id, userId, key, value);
    }
    
    public void UpdateValue(string? newValue)
    {
        if (newValue?.Length > MaxValueLength)
        {
            throw new ArgumentException($"Value length exceeds {MaxValueLength} characters.", nameof(newValue));
        }
        Value = newValue;
    }
}

Jimmacle•4/26/25, 2:22 PM

if you change the ID then WHERE [Id] = @p3;WHERE [Id] = @p3; is never going to find the old one

JuicyOP•4/26/25, 2:22 PM

JuicyOP•4/26/25, 2:23 PM

but thats weird

JuicyOP•4/26/25, 2:23 PM

so I need to insert the userVariable to it's table before I add it to the user collection

Jimmacle•4/26/25, 2:24 PM

no, it basically means you're doing something in your EF model that is leading it to generate the wrong SQL for what actually needs to happen

JuicyOP•4/26/25, 2:24 PM

i see

JuicyOP•4/26/25, 2:25 PM

I honestly have no clue what it could be

JuicyOP•4/26/25, 2:25 PM

In the other cases I have repositories for every model that im working with

JuicyOP•4/26/25, 2:25 PM

so I just add it via reposistory before adding it to another model's collection

JuicyOP•4/26/25, 2:26 PM

but in this case I thought it would be unnecessary

JuicyOP•4/26/25, 2:34 PM

how can I check if its handled by change tracker btw?

Jimmacle•4/26/25, 2:35 PM

if you got the object from a query on the same dbcontext (that didn't use AsNoTracking), explicitly added it with Add, or is a member of an object that meets those conditions, it's handled by the change tracker

JuicyOP•4/26/25, 2:35 PM

yeah I just get it like this

    public async Task<User?> GetByIdAsync(Guid productId, Guid id, CancellationToken cancellationToken = default)
    {
        return await dbContext.Set<User>()
            .Include(u => u.Licenses)
            .Include(u => u.Machine)
            .Include(u => u.Variables)
            .FirstOrDefaultAsync(u => u.ProductId == productId && u.Id == id, cancellationToken);
    }

    public async Task<User?> GetByIdAsync(Guid productId, Guid id, CancellationToken cancellationToken = default)
    {
        return await dbContext.Set<User>()
            .Include(u => u.Licenses)
            .Include(u => u.Machine)
            .Include(u => u.Variables)
            .FirstOrDefaultAsync(u => u.ProductId == productId && u.Id == id, cancellationToken);
    }

DbConcurrencyException, what am I missing?

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