为什么我的模型中的两个外键导致外键约束？

Question

What's the workaround with this? Can this be achievable using data annotations?

public class QuestionModel
{
    [Required]
    public int Id { get; set; }

    public long AskedUserId { get; set; }
    [ForeignKey("AskedUserId")]
    public virtual ApplicationUser AskedApplicationUser { get; set; }
    public long AskerId { get; set; }
    [ForeignKey("AskerId")]
    public virtual ApplicationUser AskerApplicationUser { get; set; }
    [Required]
    public string content { get; set; }
    public bool IsAnswered { get; set; }
}

What's the problem in this model? Why do I get this error :

Introducing FOREIGN KEY constraint 'FK_Questiions_AspNetUsers_AskerId' on table 'Questiions' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. Could not create constraint or index. See previous errors.

Answer 1

You've got your ForeignKey decorations below the properties, when they should be above them. The attributes are being applied to the wrong properties.

You've also got multiple occurrences of the AskedApplicationUser property.

Try this:

public class QuestionModel
{
    [Required]
    public int Id { get; set; }

    [ForeignKey("AskedUserId")]
    public long AskedUserId { get; set; }
    [ForeignKey("AskerId")]
    public long AskerId { get; set; }
    public virtual ApplicationUser AskedApplicationUser { get; set; }
    [Required]
    public string content { get; set; }
    public bool IsAnswered { get; set; }
}