Question

假设我们有：

public class Student
{
    public int StudentID { get; set; }
    public string Name { get; set; }
}
public class Teacher
{
    public int TeacherID { get; set; }
    public string Name { get; set; }
}
public SchoolContext : DbContext
{
    public DbSet<Student> Students { get; set; }
    public DbSet<Teacher> Teachers { get; set; }
}

将其理解为下面的树是否正确？

SchoolContext
        |
        |__ DbSet<Student>
        |           |__ An entry1 (includes an Student entity, original values, current values, state of the entity)
        |           |__ An entry2 (includes an Student entity, original values, current values, state of the entity)
        |           |__ ...
        |
        |__ DbSet<Teacher>
                    |__ An entry1 (includes an Teacher entity, original values, current values, state of the entity)
                    |__ An entry2 (includes an Teacher entity, original values, current values, state of the entity)
                    |__ ...

据我所知：

学生实体是Student类的实例。
原始值是我们获取数据后该实例的开始值，例如.Find()方法。
当前值是我们修改后的值。
状态告知实体的当前状态。

Answer 1

如果您想与学生老师之间建立联系，请处理许多相关的事情。示例1：老师可以有很多学生，一个学生可以有很多老师，因此这将是多对多的关系。

这种情况下要创建另一个类

class TeacherStudent
{
    public int StudentID { get; set; }
    public Student Student { get; set; }


    public int TeacherID { get; set; }
    public Teacher Teacher { get; set; }
}

public class Student
{
    public int StudentID { get; set; }
    public string Name { get; set; }
    public List<TeacherStudent> TeacherStudents { get; set; }
}
public class Teacher
{
    public int TeacherID { get; set; }
    public string Name { get; set; }
    public List<TeacherStudent> TeacherStudents { get; set; }
}

，并在您的数据库上下文类中重写下面的方法，以便TeacherStudent成为FK关系。

protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<TeacherStudent>()
            .HasKey(s => new { s.TeacherID, s.StudentID });
    }

以下SchoolContext树是否正确？

1 个答案: