Entity framework one to one relation

Question

I'm having the following models i'm using in my app with Entity Framework 6 code first.

public class Customer
{
    public Customer
    {

    }

    public int Id { get; set; }
    public string Name { get; set; }

    public virtual Address Address { get; set; }
}


public class Address
{
    public Address
    {

    }

    public int Id { get; set; }
    public string Street { get; set; }
    public int Number { get; set; }
    public int Country { get; set; }

    public virtual Customer Customer { get; set; }              
}

When i try to save them I get the following error:

Unable to determine the principal end of an association between the types Customer and Address

Answer 1

You need to speicify the foreign key relationships. As mentioned here , try adding a [ForeignKey("CustomerId")] over public virtual Customer Customer { get; set; } public virtual Customer Customer { get; set; } public virtual Customer Customer { get; set; } and [ForeignKey("AddressId")] over public virtual Address Address { get; set; } public virtual Address Address { get; set; } public virtual Address Address { get; set; } , and add those id fields to the model. Such As:

public class Customer
{
    public Customer
    {

    }

    public int Id { get; set; }
    public string Name { get; set; }
    public int Addressid { get; set; }

    [ForeignKey("AddressId")]
    public virtual Address Address { get; set; }
}


public class Address
{
    public Address
    {

    }

    public int Id { get; set; }
    public string Street { get; set; }
    public int Number { get; set; }
    public int Country { get; set; }
    public int CustomerId { get; set; }

    [ForeignKey("CustomerId")]
    public virtual Customer Customer { get; set; }              
}