当相关表首先引用时,一对一上的EF迁移问题

我在公司和公司之间有一种1:1的关系,就像这样创建的图表:

public class Company
{
    public Company()
    {
        Contacts = new HashSet<Contact>();
    }

    [Key]
    public int CompanyId { get; set; }

    public string Name { get; set; }

    [ForeignKey("CompanyId")]
    public virtual CompanyDemographic Demographic { get; set; }

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

public class CompanyDemographic
{
    [Key]
    [ForeignKey("Company")]
    public int CompanyId { get; set; }
    public virtual Company Company { get; set; }

    public int EmployeeCount { get; set; }
}

迁移构建正确,一切正常。

然后,我在CompanyDemographic中添加了一个引用,如下所示:

public class CompanyDemographic
{
    [Key]
    [ForeignKey("Company")]
    public int CompanyId { get; set; }
    public virtual Company Company { get; set; }

    public int EmployeeCount { get; set; }

    // ADDING THIS
    [ForeignKey("CurrentProvider")]
    public int CurrentProviderCompanyId { get; set; }
    public virtual Company CurrentProvider { get; set; }
}

当我添加迁移时,看起来是这样的:

public override void Up()
{
    DropForeignKey("dbo.Contacts", "CompanyId", "dbo.Companies");
    DropForeignKey("dbo.CompanyDemographics", "CompanyId", "dbo.Companies");
    DropPrimaryKey("dbo.Companies");
    AddColumn("dbo.CompanyDemographics", "CurrentProviderCompanyId", c => c.Int(nullable: false));
    AlterColumn("dbo.Companies", "CompanyId", c => c.Int(nullable: false));
    AddPrimaryKey("dbo.Companies", "CompanyId");
    CreateIndex("dbo.Companies", "CompanyId");
    CreateIndex("dbo.CompanyDemographics", "CurrentProviderCompanyId");
    AddForeignKey("dbo.CompanyDemographics", "CurrentProviderCompanyId", "dbo.Companies", "CompanyId", cascadeDelete: true);
    AddForeignKey("dbo.Contacts", "CompanyId", "dbo.Companies", "CompanyId", cascadeDelete: true);
    AddForeignKey("dbo.CompanyDemographics", "CompanyId", "dbo.Companies", "CompanyId");
}

它试图删除所有的键并重建。如何避免这种情况?