Question

Person是包含所有用户的用户模型。更改模型包括EngineerId和ManagerId，两者都是Person ID。为什么我会收到此错误？

无法在ProjectName.Models.Change类型上确定外键的复合外键排序。在复合外键属性上使用ForeignKey数据注释时，请确保使用Column data annotation或Fluent API指定顺序。

public class Change
{
    [Key]
    public int ChangeId { get; set; }

    [Required(ErrorMessage = "Change description is required.")]
    [Display(Name = "Change Description")]
    [DataType(DataType.MultilineText)]
    public string ChangeDescription { get; set; }

    [Required(ErrorMessage = "Change date is required.")]
    [Display(Name = "Date of Change")]
    [DataType(DataType.Date)]
    public DateTime ChangeDate { get; set; }

    [Required(ErrorMessage = "Time is required.")]
    [Display(Name = "Time of Change")]
    [DataType(DataType.Time)]
    public DateTime ChangeTime { get; set; }

    [Required(ErrorMessage = "Engineer name is required.")]
    [Display(Name = "Engineer")]
    [ForeignKey("person")]
    public int EngineerId { get; set; }

    [Required(ErrorMessage = "Status is required.")]
    [Display(Name = "Status")]
    public int StatusId { get; set; }

    [Required(ErrorMessage = "Manager is required.")]
    [Display(Name = "Manager")]
    [ForeignKey("person")]
    public int ManagerId { get; set; }

    [Required(ErrorMessage = "System is required.")]
    [Display(Name = "System")]        
    public int SystemDetailId { get; set; }

    public virtual Person person { get; set; }
    public virtual Status status { get; set; }
    public virtual SystemDetail systemdetail { get; set; }
}

Answer 1

您有2个外键属性（EngineerId和ManagerId）已与相同的导航属性（ForeignKey关联（通过person属性）。通过这种方式，EF认为它们形成了一个复合键，因此您将获得例外。

因为（如果我理解正确）你的意图是有2个关系，你需要将每个外键与一个单独的导航属性相关联。以下是您需要更改的重要部分：

public class Change
{
    // ...

    [Required(ErrorMessage = "Engineer name is required.")]
    [Display(Name = "Engineer")]
    [ForeignKey("Engineer")]
    public int EngineerId { get; set; }

    [Required(ErrorMessage = "Manager is required.")]
    [Display(Name = "Manager")]
    [ForeignKey("Manager")]
    public int ManagerId { get; set; }

    // instead of person property:
    public virtual Person Engineer { get; set; }
    public virtual Person Manager { get; set; }
}

无法确定外键的复合外键排序

1 个答案: