如何通过继承映射实体-Entity Framework Core 2.0

Question

I have a .net core 2.0 project and I'm using Entity Framework Core 2.0 I want to map an entity that has an inheritance and this inheritance has an inheritance too

My entity which I want to map in [Domain.Project] :

public class Customer : BaseEntity
{
    public Customer(Name name, DateTime? birthDay, Email email, string password, List<CreditDebitCard>  creditDebitCards = null)
    {
            CreationDate = DateTime.Now;
            Name = name;
            BirthDay = birthDay;
            Email = email;
            Password = password;
            _CreditDebitCards = creditDebitCards ?? new List<CreditDebitCard>();
    }

    [Fields...]
    [Properties...]
    [Methods...]
}

My BaseEntity class in [Domain.Project] :

public abstract class BaseEntity : Notifiable
{
    public BaseEntity()
    {
            CreationDate = DateTime.Now;
            IsActive = true;
    }

    [Fields...]
    [Properties...]
    [Methods...]
}

My Notifiable class (look, it have a list of Notification type) in [Shared.Project] :

public abstract class Notifiable
{
    private readonly List<Notification> _notifications;

    protected Notifiable() { _notifications = new List<Notification>(); }

    public IReadOnlyCollection<Notification> Notifications => _notifications;
    [Methods...]
}

My Notification class in [Shared.Project] :

public class Notification
{
    public Notification(string property, string message)
    {
        Property = property;
        Message = message;
    }

    public string Property { get; private set; }
    public string Message { get; private set; }
}

My Entity Framework context class in [Infra.Project] :

public class MoFomeDataContext : DbContext
{
    public DbSet<Customer> Customers { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer(Runtime.ConnectionString);
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<CreditDebitCard>().Map();
    }
}

My Mapping class in [Infra.Project] :

public static class CustomerMap
{ 
    public static EntityTypeBuilder<Customer> Map(this EntityTypeBuilder<Customer> cfg)
    {
        cfg.ToTable("Customer");
        cfg.HasKey(x => x.Id);
        cfg.Property(x => x.BirthDay).IsRequired();
        cfg.OwnsOne(x => x.Email);
        cfg.OwnsOne(x => x.Name);
        cfg.HasMany(x => x.CreditDebitCards);

        return cfg;
    }
}

When I try add a migration, I get this error:

The entity type 'Notification' requires a primary key to be defined.

But neither the Notification class and neither the Notifiable class have been mapped in my context, they must not be mapped.

I do it in .net full framework and it works here is the .net full framework code

Answer 1

By convention EF Core discovers and maps all properties of the entity class and all its base classes . In your case, Notifications property is discovered and identified as collection navigation property , hence the element type Notification is mapped as entity.

It's because the default assumption is that the entity model represent a store model . The members representing non store attributes should be unmapped explicitly. To fix the issue, just add the following to your OnModelCreating override:

modelBuilder.Ignore<Notification>();

References:

• Including & Excluding Types
• Including & Excluding Properties
• Relationships