Entity Framework 导航属性(2)

1.学校

 

[Table("School")]
public partial class School
{
    public School()
    {
        Students = new List<Student>();
        Teachers = new List<Teacher>();
    }
    [Key]
    public string SchoolId { get; set; }

    public string Name { get; set; }

    public virtual ICollection<Student> Students { get; set; }

    public virtual ICollection<Teacher> Teachers { get; set; }
}

 

2.学生

[Table("Student")]
public partial class Student
{
    public Student()
    {
        Teachers = new List<Teacher>();
    }
    [Key]
    public string StudentId { get; set; }

    public string Name { get; set; }

    public string PhoneId { get; set; }

    public string SchoolId { get; set; }

    public virtual School School { get; set; }

    public ICollection<Teacher> Teachers { get; set; }
}

 

3.教师

[Table("Teacher")]
public class Teacher
{
    public Teacher()
    {
        Students = new List<Student>();
    }
    [Key]
    public string TeacherId { get; set; }

    public string Name { get; set; }

    public string PhoneId { get; set; }

    public string SchoolId { get; set; }

    public virtual School School { get; set; }

    public virtual ICollection<Student> Students { get; set; }
}

 

上面三个数据表映射成的实体类，关系是学校有多个学生和老师，每个学生和老师互相对应多个

关系配置在DbContext的OnModelCreating方法中配置

一对多

 

modelBuilder.Entity<Student>()
    .HasRequired(a => a.School)
    .WithMany(a => a.Students)
    .HasForeignKey(a=>a.StudentId);
modelBuilder.Entity<Teacher>()
    .HasRequired(a => a.School)
    .WithMany(a => a.Teachers)
    .HasForeignKey(a => a.TeacherId);

 

 

 

多对多

 

modelBuilder.Entity<Teacher>()
    .HasMany(a => a.Students)
    .WithMany(a => a.Teachers)
    .Map
    (
        a =>
        {
            a.MapLeftKey("TeacherId"); 
            a.MapRightKey("StudentId");
            a.ToTable("Teacher_Student");
        }

    );