c# – Entity Framework可选：可选关系

在我的情况下,有时存在指向BaseTable记录的AdditionalData记录,但有时BaseTable或AdditionalData记录存在而没有任何链接. BaseTable的外键(如果存在)位于AdditionalData表上.

我希望能够在BaseTable和可能连接的任何AdditionalDatas之间来回导航.

BaseTable  0..1 ----- 0..1 AdditionalData1
                 
                  --- 0..1 AdditionalData2

public class BaseTable {
    public int Id { get; set; }
    public virtual AdditionalType1 AdditionalType1 { get; set; }
    public virtual AdditionalType2 AdditionalType2 { get; set; }
}                  

public class AdditionalType1 {
    public int Id { get; set; }
    public int? BaseTableId { get; set; }
    public virtual BaseTable BaseTable { get; set; }
}

public class AdditionalType2 {
    public int Id { get; set; }
    public int? BaseTableId { get; set; }
    public virtual BaseTable BaseTable { get; set; }
}

我该如何工作？我得到了：

modelBuilder.Entity<AdditionalType1>()
    .HasOptional(zmt => zmt.BaseTable)
    .WithOptionalDependent(zm => zm.AdditionalType1)
    .Map(a => a.MapKey("BaseTableId"));
modelBuilder.Entity<AdditionalType2>()
    .HasOptional(zmt => zmt.BaseTable)
    .WithOptionalDependent(zm => zm.AdditionalType2)
    .Map(a => a.MapKey("BaseTableId"));

但它告诉我这个：

error: (1564,6) : error 0019: Each property name in a type must be
unique. Property name ‘BaseTableId’ was already defined.

我不知道究竟是什么意思,也不确定如何修复.

编辑：如果我删除这里建议的Map / MapKey子句(https://stackoverflow.com/a/8016308/237091)我得到此错误,当一个查询运行使用它时：

Invalid column name ‘BaseTable_Id’
as it maps itself to BaseTable_Id automatically instead of my BaseTableId field.