C#•3mo ago

Entity Framework Core 8 -Foreign Key Constraint failure.

Hello, I am playing around with EF code first and I am trying to model 3 tables:

Product newProduct = new()
        {   
            Id = guid,
            CreatedAt = DateTime.Now,
            UpdatedAt = DateTime.Now,
            Name = ProductNutritionModel.Product.Name,
            Weight = 10,
            IsVegan = false,
            IsVegetarian = false,
            Rating = Random.Shared.Next(1, 10),
            NutritionalValue = new NutritionalValue
            {   
                EnergeticValue = 10,
                Fat = 50,
                SaturatedFats = 30,
                Carbohydrate = 40,
                Sugar = 20,
                Protein = Random.Shared.Next(15, 100),
                Salt = Random.Shared.Next(12, 100),
                ProductId = guid
            }
        };
        
        if (existingDNI is not null)
        {
            existingDNI.Products.Add(newProduct);
            foreach (var existingDniProduct in existingDNI.Products)
            {
                existingDniProduct.DailyNutritionInfoId = existingDniProduct.Id;
            }

            var saveResult = await DbContext.SaveChangesAsync();
            if (saveResult > 0)
            {
                Navigation.NavigateTo("");
            }
        }
        else
        {
            DailyNutritionInfo newDailyNutritionInfo = new()
            {   
                Id = Guid.NewGuid(),
                CreatedAt = DateTime.Today,
                Products = [newProduct],
            };

            DbContext.DailyNutritionInfos.Add(newDailyNutritionInfo);

            var result = await DbContext.SaveChangesAsync();
            if (result > 0)
            {
                Navigation.NavigateTo("");
            }
        }

Product newProduct = new()
        {   
            Id = guid,
            CreatedAt = DateTime.Now,
            UpdatedAt = DateTime.Now,
            Name = ProductNutritionModel.Product.Name,
            Weight = 10,
            IsVegan = false,
            IsVegetarian = false,
            Rating = Random.Shared.Next(1, 10),
            NutritionalValue = new NutritionalValue
            {   
                EnergeticValue = 10,
                Fat = 50,
                SaturatedFats = 30,
                Carbohydrate = 40,
                Sugar = 20,
                Protein = Random.Shared.Next(15, 100),
                Salt = Random.Shared.Next(12, 100),
                ProductId = guid
            }
        };
        
        if (existingDNI is not null)
        {
            existingDNI.Products.Add(newProduct);
            foreach (var existingDniProduct in existingDNI.Products)
            {
                existingDniProduct.DailyNutritionInfoId = existingDniProduct.Id;
            }

            var saveResult = await DbContext.SaveChangesAsync();
            if (saveResult > 0)
            {
                Navigation.NavigateTo("");
            }
        }
        else
        {
            DailyNutritionInfo newDailyNutritionInfo = new()
            {   
                Id = Guid.NewGuid(),
                CreatedAt = DateTime.Today,
                Products = [newProduct],
            };

            DbContext.DailyNutritionInfos.Add(newDailyNutritionInfo);

            var result = await DbContext.SaveChangesAsync();
            if (result > 0)
            {
                Navigation.NavigateTo("");
            }
        }

I can add 1 Product entity to the DailyNutrition collection, but if I try to add more I am getting the "Foreign Key Constraint" error. To be honest it's unclear to me which FK is referring to.

48 Replies

FusedQyou•3mo ago

The error would specify what the actual missing constraint is

Lamar•3mo ago

Could you tell me where to look for this? I will paste screenshots where i've been looking for:

leowest•3mo ago

well the way u made it, its one to one

Lamar•3mo ago

You mean Product - NutritionalValue? DailyInfo - Product I hope its one to many Will take a look in a bit

leowest•3mo ago

Well what ur saying is that X should accept more than one of Y And at least from the 3 models u provided I did not see anything that would allow for that

Lamar•3mo ago

Shouldn't DailyInfo have a collection of Products. And in turn each product shold have 1 NutritionalValue reference

leowest•3mo ago

if DailyNutrition is supposed to accept multiple products then yes its what composes a one to many https://learn.microsoft.com/en-us/ef/core/modeling/relationships/one-to-many

Lamar•3mo ago

Yes, that's how I wanted it to be. I will remove the reference to the related entity and test how that works out, should be fine since there are only 2 It seems it's related to the DailyNutritionInfo - Product relationship

leowest•3mo ago

well u have to remove/update the migration with the updates or modify the table ofc that depends how ur doing it dbfirst or codefirst

Lamar•3mo ago

I am doing it codefirst, I've been dropping the db and creating a fresh migration for each change

leowest•3mo ago

sure, can you $paste your models to the below site?

MODiX•3mo ago

If your code is too long, you can post to https://paste.mod.gg/ and copy the link into chat for others to see your shared code!

leowest•3mo ago

or if u got it working just ignore it 😛

Lamar•3mo ago

Will do, I didnt get to make it to work yet

Lamar•3mo ago

https://paste.mod.gg/nhjclnsxalbs/0

BlazeBin - nhjclnsxalbs

A tool for sharing your source code with the world!

Lamar•3mo ago

Should I also paste the code where I am trying to create these entities? Maybe I am doing something wrong there

Lamar•3mo ago

https://paste.mod.gg/tzuvdmmgkyir/0

BlazeBin - tzuvdmmgkyir

A tool for sharing your source code with the world!

leowest•3mo ago

that cuts me the job of doing it my self to test so thx

Lamar•3mo ago

Thanks a lot btw. I guess I can just paste the whole component. Will update

Lamar•3mo ago

https://paste.mod.gg/tcaeoqnibbqx/0

BlazeBin - tcaeoqnibbqx

A tool for sharing your source code with the world!

leowest•3mo ago

    public class Product
    {
        public Guid Id { get; set; }
        public DateTimeOffset CreatedAt { get; set; }
        public DateTimeOffset UpdatedAt { get; set; }
        [MaxLength(100)]
        public required string Name { get; set; }
        public double Weight { get; set; }
        public bool IsVegan { get; set; }
        public bool IsVegetarian { get; set; }
        public int Rating { get; set; }
        public Guid DailyNutritionInfoId { get; set; }
        public DailyNutritionInfo DailyNutritionInfo { get; set; } = null!;
    }

    public class ProductConfiguration : IEntityTypeConfiguration<Product>
    {
        public void Configure(EntityTypeBuilder<Product> builder)
        {
            builder.HasOne(x => x.DailyNutritionInfo)
                .WithMany(n => n.Products)
                .HasForeignKey(x => x.DailyNutritionInfoId);
        }
    }

    public class DailyNutritionInfo
    {
        public Guid Id { get; set; }
        public DateTime CreatedAt { get; set; }
        public DateTime UpdatedAt { get; set; }
        public ICollection<Product> Products { get; set; } = = null!;
    }

    public class Product
    {
        public Guid Id { get; set; }
        public DateTimeOffset CreatedAt { get; set; }
        public DateTimeOffset UpdatedAt { get; set; }
        [MaxLength(100)]
        public required string Name { get; set; }
        public double Weight { get; set; }
        public bool IsVegan { get; set; }
        public bool IsVegetarian { get; set; }
        public int Rating { get; set; }
        public Guid DailyNutritionInfoId { get; set; }
        public DailyNutritionInfo DailyNutritionInfo { get; set; } = null!;
    }

    public class ProductConfiguration : IEntityTypeConfiguration<Product>
    {
        public void Configure(EntityTypeBuilder<Product> builder)
        {
            builder.HasOne(x => x.DailyNutritionInfo)
                .WithMany(n => n.Products)
                .HasForeignKey(x => x.DailyNutritionInfoId);
        }
    }

    public class DailyNutritionInfo
    {
        public Guid Id { get; set; }
        public DateTime CreatedAt { get; set; }
        public DateTime UpdatedAt { get; set; }
        public ICollection<Product> Products { get; set; } = = null!;
    }

it would be something like this

Lamar•3mo ago

But this way there will be a one to many between products and NutritinalValue

leowest•3mo ago

ah my bad u want it to DailyNutrition the idea is the same

Lamar•3mo ago

protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder
            .Entity<DailyNutritionInfo>()
            .HasMany(d => d.Products)
            .WithOne(p => p.DailyNutritionInfo)
            .HasForeignKey(p => p.DailyNutritionInfoId).IsRequired();
    }

protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder
            .Entity<DailyNutritionInfo>()
            .HasMany(d => d.Products)
            .WithOne(p => p.DailyNutritionInfo)
            .HasForeignKey(p => p.DailyNutritionInfoId).IsRequired();
    }

I have added this, but it behaves the same

leowest•3mo ago

but wasn't the issue that u were trying to add more than one nutritionvalue to products rrr products to nutrition value*

Lamar•3mo ago

No it's the other way around I can add 1 product to a dailyNutritonalInfo But when I try to add more I get that fk issue I have completely commeted out and made a migration without the nutritional value part

leowest•3mo ago

ok let me update sec updated the above

Lamar•3mo ago

It's the way I have it also I guess this means I am not creating it properly in blazor

leowest•3mo ago

that should work, let me give it atry works for me

Lamar•3mo ago

well Could you share how you created the entities before saving them?

leowest•3mo ago

ah ok I see the problem u should not set the id the db sets it mm unsure if sqlite handles guid thou

Lamar•3mo ago

Which one? On the Product? Or on each product for the DailyNutrition FK?

leowest•3mo ago

            Product newProduct = new()
            {
                CreatedAt = DateTimeOffset.UtcNow,
                UpdatedAt = DateTimeOffset.UtcNow,
                Name = $"Product {id}",
                Weight = Random.Shared.Next(2, 10),
                IsVegan = Random.Shared.Next(0, 2) == 1,
                IsVegetarian = Random.Shared.Next(0, 2) == 1,
                Rating = Random.Shared.Next(1, 10),
                DailyNutritionInfo = new DailyNutritionInfo
                {
                    CreatedAt = DateTimeOffset.UtcNow,
                    UpdatedAt = DateTimeOffset.UtcNow
                }
            };

            Product newProduct = new()
            {
                CreatedAt = DateTimeOffset.UtcNow,
                UpdatedAt = DateTimeOffset.UtcNow,
                Name = $"Product {id}",
                Weight = Random.Shared.Next(2, 10),
                IsVegan = Random.Shared.Next(0, 2) == 1,
                IsVegetarian = Random.Shared.Next(0, 2) == 1,
                Rating = Random.Shared.Next(1, 10),
                DailyNutritionInfo = new DailyNutritionInfo
                {
                    CreatedAt = DateTimeOffset.UtcNow,
                    UpdatedAt = DateTimeOffset.UtcNow
                }
            };

for example in this example it will give both an id now say u do

            var nutrition = ctx.DailyNutritionInfo.FirstOrDefault();
            Product newProduct = new()
            {
                CreatedAt = DateTimeOffset.UtcNow,
                UpdatedAt = DateTimeOffset.UtcNow,
                Name = $"Product {id}",
                Weight = Random.Shared.Next(2, 10),
                IsVegan = Random.Shared.Next(0, 2) == 1,
                IsVegetarian = Random.Shared.Next(0, 2) == 1,
                Rating = Random.Shared.Next(1, 10),
                DailyNutritionInfo = nutrition
            };

            var nutrition = ctx.DailyNutritionInfo.FirstOrDefault();
            Product newProduct = new()
            {
                CreatedAt = DateTimeOffset.UtcNow,
                UpdatedAt = DateTimeOffset.UtcNow,
                Name = $"Product {id}",
                Weight = Random.Shared.Next(2, 10),
                IsVegan = Random.Shared.Next(0, 2) == 1,
                IsVegetarian = Random.Shared.Next(0, 2) == 1,
                Rating = Random.Shared.Next(1, 10),
                DailyNutritionInfo = nutrition
            };

this 2nd product will be using the already existent nutrition

Lamar•3mo ago

Oh OK, then should I assign the reference to the existing nutrition

leowest•3mo ago

if u don't want to create a new item yes

Lamar•3mo ago

No, I want it to be added to an existing dailyNutrition for the currentDay Let me try it out

leowest•3mo ago

first one is dailynutrition created so u can see 2 second one are products using referencing the 2

Lamar•3mo ago

But if I add a reference to the Product of the DailyNutrition Should I also update manualy the lists of products inside DailyNutrition?

leowest•3mo ago

if you're doing it the opposite way yes u would be adding a product to it u dont need to do both thou if u already set either the GUID on DailyNutritionInfoId or gave it the reference on DailyNutritionInfo then u dont need to add it to the collection and if u add product to the collection then u dont need to add the references to product as I understand it i.e.: if I do

var p = new Product { DailyNutritionInfoId = Guid.Parse("395fe9c1-f0d6-4224-8720-610f8cd6f6bd") };

var p = new Product { DailyNutritionInfoId = Guid.Parse("395fe9c1-f0d6-4224-8720-610f8cd6f6bd") };

this is fine, if I do

var p = new Product { DailyNutritionInfo = reference };

var p = new Product { DailyNutritionInfo = reference };

this is also fine

var p = new Product...
n.Products.Add(p); // n is a reference to a dailynutritioninfo

var p = new Product...
n.Products.Add(p); // n is a reference to a dailynutritioninfo

also fine you dont need to do all, just one of the above

Lamar•3mo ago

It worked Thanks a lot This was the issue, I was doing both things cue the FK constraint issue

leowest•3mo ago

if u do both they collide

Lamar•3mo ago

That's a relief

leowest•3mo ago

if u have no further questions throw a /close to mark it as solved 😉

Lamar•3mo ago

I don't have any questions about this right now. Will continue fighting adding Identity now 🙃 . Thanks a bunch!

leowest•3mo ago

well unhappily I won't able to help u with identity asp.net side but gl

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Entity Framework Core 8 -Foreign Key Constraint failure.