Question

您好我正在创建Web应用程序，并且已经安装了 Microsoft.entityFrameworkCore 和 Microsoft.entityFrameworkCore.Tools 。

在包管理器控制台中执行添加迁移的过程中，我收到错误

＆＃34; System.InvalidOperationException：实体类型＆＃39;参加＆＃39;具有使用数据注释定义的复合主键。要设置复合主键，请使用流畅的API ＆＃34;

这是我在实体文件夹中的代码。

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Threading.Tasks;

namespace _3241_farmDb.Entities
{

    public class Farm
    {
        [Required, MaxLength(30)]
        [Key]
        public string FarmName { get; set; }
        [Required, MaxLength(15)]
        public string FarmCity { get; set; }
        [Required, MaxLength(9)]
        public string FarmerSSN { get; set; }
    }
    public class Farmer
    {
        [Required, MaxLength(9)]
        [Key]
        public int SS { get; set; }
        [Required, MaxLength(9)]
        public string Fname { get; set; }
        [Required, MaxLength(15)]
        public string Lname { get; set; }
        [Required, MaxLength(15)]
        public string CityName { get; set; }
        [Required, MaxLength(15)]
        public string Address { get; set; }
        [Required, MaxLength(30)]
        public string BoardPositionName { get; set; }
    }
    public class Child
    {
        [Required, MaxLength(9)]
        [Key]
        public int FarmerSS { get; set; }
        [Required, MaxLength(15)]
        [Key]
        public string Fname { get; set; }
        [Required, MaxLength(15)]
        [Key]
        public string Lname { get; set; }
        [Required]
        public int Age { get; set; }
    }
    public class Attends
    {

        [Key, Column(Order = 1)]
        public int FarmerSS { get; set; }
        [Key, Column(Order = 2)]
        public int HotelID { get; set; }
        [Required, MaxLength(15)]
        public string BoardPosition { get; set; }
    }

    public class Livestock
    {
        [Required, MaxLength(15)]
        public int LivestockID { get; set; }
        [Required, MaxLength(15)]
        public string LivestockType { get; set; }
    }
    public class Farm_Houses
    {
        [Required, MaxLength(15)]
        [Key]
        public int LivestockID { get; set; }
        [Required, MaxLength(15)]
        public string FarmName { get; set; }
    }
    public class Crops
    {
        [Required, MaxLength(15)]
        [Key]
        public int CropID { get; set; }
        [Required, MaxLength(15)]
        public string CropName { get; set; }
    }
}

如何调整它以正确设置复合键？

Answer 1

在 EF核心..

只能使用Fluent API配置复合键 - 约定永远不会设置复合键，您不能使用数据用于配置一个的注释。

以下是 Fluent API 版本：

注意： 这只是一个例子。请根据您的使用情况进行调整。

protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Attends>()
            .HasKey(c => new { c.FarmerSS, c. HotelID });
    }

您可以在此处详细了解：composite key

ASP.NET添加迁移＆复合主键错误＆＃39;如何使用流畅的API

1 个答案: