.Net Core MVC 从模型更新数据库错误

Question

抱歉，如果这看起来有点基本，我正在尝试为我正在构建的网站进行迁移，并且在创建迁移后尝试更新数据库时，我不断收到此错误。有谁知道我该如何解决这个问题？

这是模型的代码：

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Text;

namespace BulkyBook.Models
{
    public class ShoppingCart
    {
        public ShoppingCart()
        {
            Count = 1;
        }
        [Key]
        public int Id { get; set; }

        public string ApplicationUserId { get; set; }
        [ForeignKey("ApplicationUserId")]
        public ApplicationUser ApplicationUser { get; set; }

        public int ProductId { get; set; }
        [ForeignKey("ProductId")]
        public Product Product { get; set; }


        [Range(1, 1000, ErrorMessage = "Please enter a value between 1 and 1000")]
        public int Count { get; set; }

        [NotMapped]
        public double Price { get; set; }

    }
}

订单详情：

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Text;

namespace BulkyBook.Models
{
    public class OrderDetails
    {
        [Key]
        public int Id { get; set; }

        [Required]
        public int OrderId { get; set; }
        [ForeignKey("OrderId")]
        public OrderHeader OrderHeader { get; set; }


        [Required]
        public int ProductId { get; set; }
        [ForeignKey("ProductId")]
        public Product Product { get; set; }

        public int Count { get; set; }
        public double Price { get; set; }
    }
}

产品：

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Text;

namespace BulkyBook.Models
{
    public class Product
    {
        public int Id { get; set; }
        [Required]
        public string Title { get; set; }
        [Required]
        public string Description { get; set; }
        [Required]
        public string ISBN { get; set; }
        [Required]
        public string Author { get; set; }
        [Required]
        [Range(1, 10000)]
        public double ListPrice { get; set; }
        [Required]
        [Range(1, 10000)]
        public double Price { get; set; }
        [Required]
        [Range(1, 10000)]
        public double Price50 { get; set; }
        [Required]
        [Range(1, 10000)]
        public double Price100 { get; set; }

        public string ImageUrl { get; set; }

        [Required]
        public int CategoryId { get; set; }
        [ForeignKey("CategoryId")]
        public Category Category { get; set; }

        [Required]
        public int CoverTypeId { get; set; }
        [ForeignKey("CoverTypeId")]
        public CoverType CoverType { get; set; }

    }
}

Nuget Package manager console error after Update-Db

Answer 1

解决它 您必须在 orderdetials 表中将属性“productid”定义为 Nullable