[英]ForeignKey error in Entity Framework
我正在计划一个简单的两个表结构:
1)教师桌:
public class TeacherAccount
{
[DataType(DataType.Text), Required()]
public string Name { get; set; }
[DataType(DataType.Text), Required()]
public string Address { get; set; }
[DataType(DataType.EmailAddress), Required(), Key]
public string Email { get; set; }
[DataType(DataType.Password), Required()]
public string Password { get; set; }
[DataType(DataType.Password), Compare("Password"), Required(), NotMapped]
public string ConfirmPassword { get; set; }
public bool Activated { get; set; }
}
2)老师教授的科目:
public class Teacher_Subject_Map
{
[ForeignKey("TeacherAccount")]
public string Email { get; set; }
public string Subjects;
}
我的概念是:对于确定一名教师的电子邮件,可以有多个科目,由该教师教。
我怎么得到这个:
类型为'xpertsdesk.Models.Teacher_Subject_Map'的属性'Email'上的ForeignKeyAttribute无效。 在依赖类型“ xpertsdesk.Models.Teacher_Subject_Map”上找不到导航属性“ TeacherAccount”。 Name值应为有效的导航属性名称。
作为MVC5中的错误。
我正在尝试做的是:
Create table Teacher(Email varchar(30) Primary Key, Other Details);
Create table Subjects(Email varchar(30) References Teacher(Email), Subject varchar(30));
我究竟做错了什么 ?
如果一个学科只能由一位老师教授(一对多关系):
在这种情况下,将没有映射表。
public class Subject
{
[Key]
public string Name { get; set; }
// This will hold the Key of Teacher
public string TeacherEmail { get; set; }
[ForeignKey("TeacherEmail")]
public virtual Teacher Teacher { get; set; }
}
public class Teacher
{
/* the original properties comes here, e.g. Email */
public string Email { get; set; }
// Navigation property for taught subjects
public virtual ICollection<Subject> Subjects { get; set; }
}
如果可以由更多的老师来授课(多对多关系):
Subject
类将是这样。
public class Subject
{
[Key]
public string Name { get; set; }
/* other properties if needed */
public virtual ICollection<Teacher> Teachers { get; set; }
}
然后,您可以在自己的DbContext类中配置多对多关系:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder
.Entity<Teacher>()
.HasMany(teacher => teacher.Subjects)
.WithMany(subject => subject.Teachers)
.Map(c =>
{
c.ToTable("Teacher_Subject_Map");
c.MapLeftKey("TeacherEmail");
c.MapRightKey("SubjectName");
});
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.