EntityFramework 核心流利 API

Question

我有两个 table：估计值Activity 和 Activity:

public class EstimationActivity 
{
    public Guid Id { get; set; }

    public Guid EstimateId { get; set; }
    public virtual Estimate Estimate { get; set; }

    public Guid ParentActivityId { get; set; }
    public virtual Activity ParentActivity { get; set; }

    public Guid ActivityId { get; set; }
    public virtual Activity Activity { get; set; }

    public double Duration { get; set; }

    [Range(minimum: 0, maximum: 100)]
    public int Contingency { get; set; }

    public ICollection<Note> Notes { get; set; } = new List<Note>();
}

public class Activity
{
    public Guid Id { get; set; }

    public Guid ActivityTypeId { get; set; }
    public virtual ActivityType ActivityType { get; set; }

    public Guid RfcAreaId { get; set; }
    public virtual RfcArea RfcArea { get; set; }

    [Required]
    [StringLength(maximumLength: 60, MinimumLength = 5)]
    public string Name { get; set; }
}

如您所见，Activity table(class) 有两个外键。当我尝试添加迁移时，我得到：

Introducing FOREIGN KEY constraint 'FK_EstimateActivities_Activities_ParentActivityId' on table 'EstimateActivities' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.

我试图用它来限制所有级联删除，正如我在几篇文章中发现的那样：

protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        foreach (var relationship in modelBuilder.Model.GetEntityTypes().SelectMany(e => e.GetForeignKeys()))
        {
            relationship.DeleteBehavior = DeleteBehavior.Restrict;
        }

        base.OnModelCreating(modelBuilder);
    }

这没有起到作用。我应该如何解决错误？

Answer 1

尝试在设置 FK 的地方使用属性 [ForeignKey("SomeId")]，[InverseProperty("OtherClass")] 覆盖此约定并指定属性的对齐方式。

    public class EstimationActivity
{
    public Guid Id { get; set; }

    public Guid EstimateId { get; set; }
    public virtual Estimate Estimate { get; set; }

    public Guid ParentActivityId { get; set; }

    [ForeignKey("ParentActivityId")]
    public virtual Activity ParentActivity { get; set; }

    public Guid ActivityId { get; set; }

    [ForeignKey("ActivityId")]
    public virtual Activity Activity { get; set; }

    public double Duration { get; set; }

    [Range(minimum: 0, maximum: 100)]
    public int Contingency { get; set; }

    public ICollection<Note> Notes { get; set; } = new List<Note>();
}

public class Activity
{
    public Guid Id { get; set; }

    public Guid ActivityTypeId { get; set; }
    public virtual ActivityType ActivityType { get; set; }

    public Guid RfcAreaId { get; set; }
    public virtual RfcArea RfcArea { get; set; }

    [Required]
    [StringLength(maximumLength: 60, MinimumLength = 5)]
    public string Name { get; set; }


    [InverseProperty("ParentActivity")]
    public virtual EstimationActivity EstimationParentActivity { get; set; }
    [InverseProperty("Activity")]
    public virtual EstimationActivity EstimationActivity { get; set; }
}

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