asp.net – EF首先使用代码与一对多关系创建重复的外键

public class Supplier
{
    public Supplier()
    {
        SupplierId = Guid.NewGuid();
    }

    public Guid SupplierId { get; set; }
    [Required]
    public string Name { get; set; }

    [Required]
    public virtual Address Address { get; set; }

    public virtual ICollection<Contact> Contacts { get; set; }
}

public class Contact
{
    public Contact()
    {
        ContactId = Guid.NewGuid();
    }

    public Guid ContactId { get; set; }

    [Required]
    public string FirstName { get; set; }
    [Required]
    public string LastName { get; set; }

    [Required]
    public Guid SupplierId { get; set; }
    [ForeignKey("SupplierId")]
    public virtual Supplier Supplier { get; set; }
}

我正在使用ASP.NET MVC 4,在创建新的Contact时,SupplierId在查询字符串中传递并作为隐藏字段添加到Contact create表单：

@Html.HiddenFor(model => model.SupplierId)

这将成功创建联系人,并使用查询字符串中的Guid填充Contact的SupplierId字段.但是,问题是Contacts表有另一个名为Supplier_SupplierId的虚拟供应商关系字段,该字段为NULL.我不确定我是否理解为什么甚至在Contacts表上创建Supplier_SupplierId,因为SupplierId应该被用作外键,这只是多余的.如果我尝试访问供应商的Contacts集合,我成功添加了Contact,则集合将返回空,因为Contact.Supplier_SupplierId为NULL.但是,如果我将SupplierId列中的值复制到Contact记录的Supplier_SupplierId列中,则Supplier.Contacts将返回Contact.

这是我的Contacts表最终看起来像：

CREATE TABLE [dbo].[Contacts] (
    [ContactId]           UNIQUEIDENTIFIER NOT NULL,[FirstName]           NVARCHAR (MAX)   NOT NULL,[LastName]            NVARCHAR (MAX)   NOT NULL,[Supplier_SupplierId] UNIQUEIDENTIFIER NULL,CONSTRAINT [PK_dbo.Contacts] PRIMARY KEY CLUSTERED ([ContactId] ASC),CONSTRAINT [FK_dbo.Contacts_dbo.Suppliers_SupplierId] FOREIGN KEY ([SupplierId]) REFERENCES [dbo].[Suppliers] ([SupplierId]),CONSTRAINT [FK_dbo.Contacts_dbo.Suppliers_Supplier_SupplierId] FOREIGN KEY ([Supplier_SupplierId]) REFERENCES [dbo].[Suppliers] ([SupplierId])
);

有谁知道为什么在联系人中创建供应商的2个外键？如何更改它以便供应商的唯一外键是SupplierId？