实体框架：如何删除相互引用的表行？

Question

如何在不出现此异常的情况下删除订单？

UserLicenses 引用 SerialOnOrderDetails 反之亦然：

DELETE 语句与 REFERENCE 约束“FK_SerialsOnOrderDetail_UserLicenses”冲突。冲突发生在数据库“sales”、表“dbo.SerialsOnOrderDetail”、列“UserLicenseId”中。

删除确认的控制器动作代码：

[Authorize(Roles = "admin")]    
[HttpPost, ActionName("Delete")]
public async Task<ActionResult> DeleteConfirmed(int id)
{
    Order order = GetOrderById(id);

    if (order.UserLicenses.Count > 0)
    {
        context.UserLicenses.RemoveRange(order.UserLicenses);
    }

    if (order.SerialsOnOrderDetails.Count > 0)
    {
        context.SerialsOnOrderDetails.RemoveRange(order.SerialsOnOrderDetails);
    }

    context.Orders.Remove(order);

    context.SaveChanges(); // Exception here !!!
}

[编辑] 添加实时数据

实时数据（Id = UserLicenseId）：

其他类：

public partial class UserLicense
{   
    public string Id { get; set; }
    public int OrderId { get; set; }
    public string ProductId { get; set; }
    public int CustomerId { get; set; }
    public string AssignedUserId { get; set; }
    public bool IsActive { get; set; }

    public virtual AspNetUser AspNetUser { get; set; }
    public virtual Customer Customer { get; set; }
    public virtual Order Order { get; set; }
    public virtual Product Product { get; set; }

    public virtual ICollection<SerialsOnOrderDetail> SerialsOnOrderDetails { get; set; }
}

public partial class SerialsOnOrderDetail
{
   public int orderID { get; set; }
   public string serial { get; set; }
   public string productID { get; set; }
   public string UserLicenseId { get; set; }
   public int customerID { get; set; }

   public virtual Product Product { get; set; }
   public virtual Serial Serial1 { get; set; }
   public virtual Order Order { get; set; }
   public virtual UserLicense UserLicense { get; set; }
   public virtual Customer Customer { get; set; }
}

public partial class Order
{
    public Order()
    {
        this.OrderDetails = new HashSet<OrderDetail>();
        this.SerialsOnOrderDetails = new HashSet<SerialsOnOrderDetail>();
        this.UserLicenses = new HashSet<UserLicense>();
    }

    public int orderID { get; set; }
    public int customerID { get; set; }
    public string promoCodeID { get; set; }
    public System.DateTime date { get; set; }
    public Nullable<int> resellerID { get; set; }
    public string invoiceID { get; set; }
    public string poNumber { get; set; }
    public Nullable<System.DateTime> paymentDate { get; set; }
    public Nullable<bool> validated { get; set; }
    public string resellerOrderID { get; set; }
    public Nullable<int> parentOrderID { get; set; }
    public int months { get; set; }

    public virtual Customer Customer { get; set; }
    public virtual ICollection<OrderDetail> OrderDetails { get; set; }
    public virtual PromoCode PromoCode { get; set; }
    public virtual Reseller Reseller { get; set; }
    public virtual ICollection<SerialsOnOrderDetail> SerialsOnOrderDetails { get; set; }
    public virtual Order ParentOrder { get; set; }
    public virtual ICollection<UserLicense> UserLicenses { get; set; }
}

Answer 1

您引用的约束消息来自底层 SQL Server。这不是 EF 错误，而是通过了。

当我在 TSQL 中遇到此类问题时，解决方案通常是在单个事务中删除两个相互引用的行。

虽然我对 EF 不是很熟悉，但通过快速搜索可以找到这个将多个操作放入单个事务上下文的示例，而不是每个操作单个事务的默认行为。

{
    context.Database.Log = Console.WriteLine;
    using (DbContextTransaction transaction = context.Database.BeginTransaction())
    {
        try
        {
            Author author1 = new Author() {    Name = "Mark" };
            Author author2 = new Author() {    Name = "John" };
            
            context.Authors.Add(author1);
            context.SaveChanges();
            
            context.Authors.Add(author2);
            context.SaveChanges();
            transaction.Commit();
        }
        catch (Exception ex)
        {
            transaction.Rollback();
        }
    }
}

我注意到另一位受访者描述了其他可能错误的事情。完全有可能我们都是对的，并且有多个问题需要解决。

Answer 2

您是否验证了 UserLicenses 和 SerialsOnOrderDetails 集合是否正确加载且不为空？你确定 removerange 是正确的方法吗？如果你不习惯的话，我建议你阅读一些关于 EF 的教程。

也许您必须使用 .Include("....") 指令更新 GetOrderById 才能加载这些集合，或者手动加载相关项目。