实体框架中的0对1关系

Question

Using EF6 Database First, I'm trying to add an association for an entity. The entity is:

public class Customer
{
    public int Id {get; set;}
    public string Name {get; set;}
    public int? ParentId {get; set;}
    public virtual Customer Parent {get; set;}
}

The Customer entity can have 0..1 related customer as Parent. After I add the navigation property and the association in the designer, and it generates the classes again, I get the following error:

Running transformation: Multiplicity is not valid in Role 'Customer1' in relationship 'FK_customers_customers'. Because the Dependent Role properties are not the key properties, the upper bound of the multiplicity of the Dependent Role must be *.

I obviously don't want a 1..n relationship because then I have a collection of parents in my customer.

Is there a workaround?

Answer 1

Have you tried creating a collection for the children? Like:

public virtual ICollection<Customer> Children { get; protected set; }