The derived type 'UserRole' cannot have KeyAttribute on property 'Id' since primary key can only be declared on the root type

Hi everyone!

Steps to reproduce

• Create ASP.NET Core application from yo generator-aspnetcore-spa with ‘Angular 2’ template (for example, with name ‘Web.Client.Spa’).
• Create .NET Core class library project (for example, with name ‘Core.DAL.Real.Database’) for EF DbContext (and create in this project EF DbContext).
• Create .NET Core class library project for domain models (for example, ‘Core.DomainModels’ and ‘Core.DomainModels.Identity’ - first project for domain models classes and second project for the ASP.NET Identity models [for EF CodeFirst approach]).

In project ‘Core.DomainModels’ add this file: IEntity.cs:

    public interface IEntity<T>
    {
        T Id { get; set; }
    }

    public interface IEntity : IEntity<Guid>
    {

    }

And in project ‘Core.DomainModels.Identity’ add this classes:

Abstract & interfaces: IUser.cs

    public interface IUser<T> : IEntity<T>
    {
        DateTime RegisterDate { get; set; }
    }

    public interface IUser : IUser<Guid>
    {

    }

IRole.cs

    public interface IRole<T> : IEntity<T>
    {
        string Name { get; set; }
    }

    public interface IRole : IRole<Guid>
    {

    }

IUserRole.cs

    public interface IUserRole<T>// : IEntity<T>
    {
        T UserId { get; set; }
        T RoleId { get; set; }

        IUser User { get; set; }
        IRole Role { get; set; }
    }

    public interface IUserRole : IUserRole<Guid>
    {

    }

Real models: User.cs

    public class User : IdentityUser<Guid>, IUser<Guid>
    {
        public static User CreateEmptyInstance()
        {
            return new User();
        }

        #region Implementation of IUser<Guid>

        public DateTime RegisterDate { get; set; }

        #endregion

        [NotMapped]
        public bool IsAuthenticated { get; set; }

    }

Role.cs

    public class Role : IdentityRole<Guid>, IRole<Guid>
    {

    }

UserRole.cs

    public class UserRole : IdentityUserRole<Guid>, IUserRole
    {

        #region Implementation of IEntity<Guid>

        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.None)]
        public Guid Id { get; set; }

        #endregion
        #region Implementation of IUserRole<Guid>

        [NotMapped]
        public IUser User { get; set; }

        [NotMapped]
        public IRole Role { get; set; }

        #endregion
    }

• Add packages ASP.NET Identity, EF Core (with Tools and Design), Npgsql to MVC App (I’m used PostgreSQL database).
• Add packages EF Core (with Tools) to Core.DAL.Real.Database project.
• In Package Manager Console run command (for startup project Core.DAL.Real.Database):

Add-Migration InitDev -Context EfDbMigrations -Environment Development

• …And I have an error:

System.InvalidOperationException: The derived type 'UserRole' cannot have KeyAttribute on property 'Id' since primary key can only be declared on the root type.    at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.KeyAttributeConvention.Apply(InternalModelBuilder modelBuilder)
    at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.OnModelBuilt(InternalModelBuilder modelBuilder) 
    at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.CreateModel(DbContext context, IConventionSetBuilder conventionSetBuilder, IModelValidator validator) 
    at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
    at Microsoft.EntityFrameworkCore.Internal.DbContextServices.CreateModel() 
    at Microsoft.EntityFrameworkCore.Internal.LazyRef`1.get_Value() 
    at Microsoft.Extensions.DependencyInjection.ServiceProvider.ScopedCallSite.Invoke(ServiceProvider provider) 
    at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetService[T](IServiceProvider provider) 
    at Microsoft.Extensions.DependencyInjection.ServiceProvider.TransientCallSite.Invoke(ServiceProvider provider) 
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.ConstructorCallSite.Invoke(ServiceProvider provider) 
    at Microsoft.Extensions.DependencyInjection.ServiceProvider.TransientCallSite.Invoke(ServiceProvider provider) 
    at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType) 
    at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider) 
    at Microsoft.EntityFrameworkCore.Design.MigrationsOperations.AddMigration(String name, String outputDir, String contextType) 
    at Microsoft.EntityFrameworkCore.Tools.Cli.MigrationsAddCommand.Execute(CommonOptions commonOptions, String name, String outputDir, String context, String environment, Action`1 reporter) 
    at Microsoft.EntityFrameworkCore.Tools.Cli.MigrationsAddCommand.<>c__DisplayClass0_0.<Configure>b__0() 
    at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args) 
    at Microsoft.EntityFrameworkCore.Tools.Cli.Program.Main(String[] args)
 The derived type 'UserRole' cannot have KeyAttribute on property 'Id' since primary key can only be declared on the root type. 

My project.json in Core.DAL.Real.Database project:

{
  "version": "1.0.0-*",

  "dependencies": {
    "NETStandard.Library": "1.6.0",
    "Microsoft.EntityFrameworkCore": "1.0.1",
    "Microsoft.EntityFrameworkCore.Tools": {
      "version": "1.0.0-preview2-final",
      "type": "build"
    },
    "Npgsql.EntityFrameworkCore.PostgreSQL": "1.0.1",
    "System.Linq": "4.1.0",
    "Core.DomainModels.Identity": "1.0.0-*",
    "Core.DomainModels": "1.0.0-*"
  },

  "frameworks": {
    "netcoreapp1.0": {      
      "imports": "dnxcore50"
    }
  },

  "tools": {
    "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final"
  } 
}

The issue

The KeyAttribute on property Id in my UserRole class must not throw this error, right? Or I do something wrong?

I found the same issue #5898 but that issue is closed by @AndriySvyryd and appropriate changes (by commit https://github.com/aspnet/EntityFramework/commit/5ce5b86d37859a1410d9e343489f8b2d3fbb9527) are included in 1.0.1 version of EF Core which I used. I’m confused because of this error. And because of this, I cannot create my first (init) migration…

Please help solve this problem…

Further technical details

EF Core version: 1.0.1 Operating system: Windows 10 Visual Studio version: VS 2015 Update 3

[AndriySvyryd]

@Cubelaster Something like this:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    ConfigureBase(modelBuilder.Entity<MyDerived>());
}

protected EntityTypeBuilder<T> ConfigureBase<T>(EntityTypeBuilder<T> entityType)
    where T : MyBase
{
    ConfigureTranslations(entityType.Property(d => d.MyTranslations));
    return entityType;
}

protected PropertyBuilder<Translations> ConfigureTranslations(PropertyBuilder<Translations> property)
    => property.HasConversion(
        v => JsonConvert.SerializeObject(v),
        v => JsonConvert.DeserializeObject<Translations>(v))
        .HasColumnType("json");

private class MyBase
{
    public string Id { get; set; }
    public Translations MyTranslations { get; set; }
}

private class MyDerived : MyBase
{
}

private class Translations
{
}

[AndriySvyryd]

@Cubelaster Avoid using the base type in OnModelCreating if you don’t want it included in the model.