SQL 錯誤：引入 FOREIGN KEY 約束可能會導致循環或多個級聯路徑。 實體框架核心

Question

我正在使用 SQL 並嘗試使用 Entity Framework Core 添加遷移。 我不確定如何解決這個問題。 它用於將評論系統與用戶和產品相關聯。 這在 SQLite 中有效。 現在使用SQL服務器。 我試圖在簡短的同時提供一切。 如果需要，我可以提供更多。 下面是我的代碼，有人可以幫忙嗎？

訪問類“程序”上的 IWebHost 時出錯。 在沒有應用程序服務提供商的情況下繼續。 錯誤：在表“ProductReviews”上引入 FOREIGN KEY 約束“FK_ProductReviews_AspNetUsers_ReviewerId”可能會導致循環或多個級聯路徑。 指定 ON DELETE NO ACTION 或 ON UPDATE NO ACTION，或修改其他 FOREIGN KEY 約束。 無法創建約束或索引。 請參閱以前的錯誤。

我已經嘗試了注釋掉的代碼。

            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

我剛試過這個：

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);
}

你沒有提供MemberReview類，所以我創建了這個：

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

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

這是結果：