SQL 错误：引入 FOREIGN KEY 约束可能会导致循环或多个级联路径。 实体框架核心

Question

我正在使用 SQL 并尝试使用 Entity Framework Core 添加迁移。 我不确定如何解决这个问题。 它用于将评论系统与用户和产品相关联。 这在 SQLite 中有效。 现在使用SQL服务器。 我试图在简短的同时提供一切。 如果需要，我可以提供更多。 下面是我的代码，有人可以帮忙吗？

访问类“程序”上的 IWebHost 时出错。 在没有应用程序服务提供商的情况下继续。 错误：在表“ProductReviews”上引入 FOREIGN KEY 约束“FK_ProductReviews_AspNetUsers_ReviewerId”可能会导致循环或多个级联路径。 指定 ON DELETE NO ACTION 或 ON UPDATE NO ACTION，或修改其他 FOREIGN KEY 约束。 无法创建约束或索引。 请参阅以前的错误。

我已经尝试了注释掉的代码。

            protected override void OnModelCreating(ModelBuilder builder)
        {
            base.OnModelCreating(builder);

    builder.Entity<MemberReview>()
                .HasKey(k => new { k.RevieweeId, k.ReviewerId });

            builder.Entity<MemberReview>().
                HasOne(u => u.Reviewer)
                .WithMany(u => u.ReviewedMembers);
                // .HasForeignKey(u => u.ReviewerId)
                // .OnDelete(DeleteBehavior.Restrict);

            builder.Entity<MemberReview>().
                HasOne(u => u.Reviewee)
                .WithMany(u => u.MemberReviews);
            // .HasForeignKey(u => u.RevieweeId)
            // .OnDelete(DeleteBehavior.Restrict);

            builder.Entity<ProductReview>()
                .HasKey(k => new { k.ReviewerId, k.ReviewedProductId });

            builder.Entity<ProductReview>().
                HasOne(u => u.ReviewedProduct)
                .WithMany(u => u.ProductReviews);
                //.HasForeignKey(u => u.ReviewedProductId)
                //.OnDelete(DeleteBehavior.Restrict);

            builder.Entity<ProductReview>().
                HasOne(u => u.Reviewer)
                .WithMany(u => u.ReviewedProducts);
                //.HasForeignKey(u => u.ReviewerId)
                //.OnDelete(DeleteBehavior.Restrict);
        }

        public class ProductReview
    {
        public Product ReviewedProduct { get; set; }
        public User Reviewer { get; set; }
        [Required]
        public int ReviewerId { get; set; }
        [Required]
        [MaxLength(30)]
        public string ReviewerUserName { get; set; }
        [Required]
        public int ReviewedProductId { get; set; }
        [Required]
        [MaxLength(35)]
        public string Title { get; set; }
        [Required]
        [MaxLength(420)]
        public string Review { get; set; }
        [Required]
        [MaxLength(2)]
        public int Rating { get; set; }
    }

        public class User : IdentityUser<int>
    {
        [Required]
        [MaxLength(12)]
        public string UserType { get; set; }
        [Required]
        public DateTime DateOfEstablishment { get; set; }
        [Required]
        [MaxLength(75)]
        public string KnownAs { get; set; }
        public DateTime Created { get; set; }
        public DateTime LastActive { get; set; }
        [MaxLength(420)]
        public string Description { get; set; }
        public ICollection<Photo> Photos { get; set; }
        public ICollection<Product> Products { get; set; }
        // REVIEW THING
        public ICollection<MemberReview> MemberReviews { get; set; }
        public ICollection<MemberReview> ReviewedMembers { get; set; }
        public ICollection<ProductReview> ReviewedProducts { get; set; }
        // *****
    }

        public class Product
    {
        public int Id { get; set; }
        [Required]
        [MaxLength(75)]
        public string Name { get; set; }
        [Required]
        [MaxLength(420)]
        public string Description { get; set; }
        public DateTime DateAdded { get; set; }
        public User User { get; set; }
        [Required]
        public int UserId { get; set; }
        // REVIEW THINGS
        public ICollection<ProductReview> ProductReviews { get; set; }
        // *****
    }

Answer 1

我刚试过这个：

protected override void OnModelCreating(ModelBuilder builder)
{
    base.OnModelCreating(builder);

    builder.Entity<MemberReview>()
        .HasKey(e => new { e.RevieweeId, e.ReviewerId });

    builder.Entity<ProductReview>()
        .HasKey(e => new { e.ReviewerId, e.ReviewedProductId });

    builder.Entity<MemberReview>()
        .HasOne<User>(e => e.Reviewer)
        .WithMany(e => e.MemberReviews)
        .HasForeignKey(e => e.ReviewerId)
        .OnDelete(DeleteBehavior.Restrict); ////////
                                                  //
    builder.Entity<MemberReview>()                //
        .HasOne<User>(e => e.Reviewee)            /// => only one of these two can be cascade
        .WithMany(e => e.ReviewedMembers)         //
        .HasForeignKey(e => e.RevieweeId)         //
        .OnDelete(DeleteBehavior.Restrict); ////////

    builder.Entity<ProductReview>()
        .HasOne<User>(e => e.Reviewer)
        .WithMany(e => e.ReviewedProducts)
        .HasForeignKey(e => e.ReviewerId)
        .OnDelete(DeleteBehavior.Restrict);
}

你没有提供MemberReview类，所以我创建了这个：

public class MemberReview
{
    public User Reviewer { get; set; }
    public int ReviewerId { get; set; }

    public User Reviewee { get; set; }
    public int RevieweeId { get; set; }
}

这是结果：