c# - 系统.Data.SqlClient.SqlException : Invalid column name 'Gender_id'

Question

我正在学习使用 asp.net mvc 和 Entity Framework 开发 Web 应用程序。我有一个包含 3 个表格学生、性别和类(class)的数据库。我遇到了这个问题。

错误在第 23 行。

Invalid column name 'Genders_Id'. Invalid column name 'Programs_Id'.

Exception Details: System.Data.SqlClient.SqlException: Invalid column name 'Genders_Id'. Invalid column name 'Programs_Id'.

Source Error:


Line 21:         {
Line 22:             StudentsContext stdContext = new StudentsContext();
Line 23:             Students students = stdContext.Students.Single(std => std.Id == id);
Line 24:             //ViewBag.Student = students;
Line 25:             return View(students);

我的 Students.cs 模型代码:

namespace WebApplication4.Models
{
  public class Students
  {
     public string Name { get; set; }
     public int Id { get; set; }
     public int Gender { get; set; }
     public int Program { get; set; }
     public string Country { get; set; }
   }
}

我的 Context.cs 文件:

public class StudentsContext:DbContext
{
    public DbSet<Students> Students { get; set; }
    public DbSet<Programs> Programs { get; set; }
    public DbSet<Genders> Genders { get; set; }
}

程序.cs:

public class Programs
{
    public int Id { get; set; }
    public string Program { get; set; }
    public List<Students> Students { get; set; }
}

性别.cs:

public class Genders
{
    public int Id { get; set; }
    public string Gender { get; set; }
    public List<Students> Students { get; set; }
}

数据库表:

Answer 1

Genders_Id 和 Programs_Id 是 FK 列的默认 EF6 约定名称，用于分别由 Genders.Students 和Programs.Students 集合导航属性。

由于您的 FK 属性/列名不是常规名称，您应该通过 [ForeinKey] 数据注释来指定它们:

public class Programs
{
    // ...
    [ForeignKey("Program")]
    public List<Students> Students { get; set; }
}

public class Genders
{
    // ...
    [ForeignKey("Gender")]
    public List<Students> Students { get; set; }
}

或(我的首选)流畅的 API:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    // ...

    modelBuilder.Entity<Genders>()
        .HasMany(e => e.Students)
        .WithRequired()
        .HasForeignKey(e => e.Gender);

    modelBuilder.Entity<Programs>()
        .HasMany(e => e.Students)
        .WithRequired()
        .HasForeignKey(e => e.Program);
}