使用EF Fluent API配置一对一关系

Question

public class Person
{
    public int PersonID { get; set; }
    public string Name { get; set; }
    public int CategoryID { get; set; }
    public virtual Category Category { get; set; }
}

public class Category
{
    public int CategoryID { get; set; }
    public string Description { get; set; }
}

So I want a one-to-one relationship between Person and Category .

1. Person must have Category (FK).
2. Deleting Category will throw Exception if some of the CategoryID still exists in Person table.

How to achieve this with EF FluentAPI?

My current code :

modelBuilder.Entity<Person>()
            .HasKey(pk => pk.PersonID)
            .HasRequired(r => r.CategoryID);

Answer 1

Take a look at this MSDN documentation on creating relationships with FluentAPI

Since the navigation property is only defined on the person object you would go with this:

modelBuilder.Entity<Person>() 
    .HasRequired(t => t.Category) 
    .WithRequiredPrincipal();

Answer 2

use this :

public class Person
{
   public int PersonID { get; set; }
   public string Name { get; set; }

   public virtual Category Category { get; set; }
}

public class Category
{
   public int CategoryID { get; set; }
   public string Description { get; set; }

   public virtual Person Person{ get; set; }
}

and with fluent api :

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Person>()
            .HasRequired(c => c.Category)
            .WithOptional(c => c.Person)
            .WillCascadeOnDelete(false);

    }