实体之间的关系（EF基础系列篇7）

public partial class Student
    {
        public int StudentID { get; set; }
        public string StudentName { get; set; }
        public Nullable<int> StandardID { get; set; }
        public string RowVersion { get; set; }
    
        public virtual Standard Standard { get; set; }
        public virtual StudentAddress StudentAddress { get; set; }
    }

 public partial class StudentAddress
    {
        public int StudentID { get; set; }
        public string Address1 { get; set; }
        public string Address2 { get; set; }
        public string City { get; set; }
        public string State { get; set; }
    
        public virtual Student Student { get; set; }
    }

 public partial class Standard
    {
        public Standard()
        {
            this.Students = new HashSet<Student>();
            this.Teachers = new HashSet<Teacher>();
        }
    
        public int StandardID { get; set; }
        public string StandardName { get; set; }
        public string Description { get; set; }
    
        public virtual ICollection<Student> Students { get; set; }
        public virtual ICollection<Teacher> Teachers { get; set; }
    }

 public partial class Teacher
    {
        public Teacher()
        {
            this.Courses = new HashSet<Course>();
        }
    
        public int TeacherID { get; set; }
        public string TeacherName { get; set; }
        public Nullable<int> StandardID { get; set; }
        public string TeacherType { get; set; }
    
        public virtual ICollection<Course> Courses { get; set; }
        public virtual Standard Standard { get; set; }
    }

 public partial class Student
    {
        public Student()
        {
            this.Course = new HashSet<Course>();
        }
    
        public int StudentID { get; set; }
        public string StudentName { get; set; }
        public Nullable<int> StandardID { get; set; }
        public string RowVersion { get; set; }
    
        public virtual Standard Standard { get; set; }
        public virtual StudentAddress StudentAddress { get; set; }
        public virtual ICollection<Course> Course { get; set; }
    }

 public partial class Course
    {
        public Course()
        {
            this.Student = new HashSet<Student>();
        }
    
        public int CourseID { get; set; }
        public string CourseName { get; set; }
        public string Location { get; set; }
        public Nullable<int> TeacherID { get; set; }
    
        public virtual Teacher Teacher { get; set; }
        public virtual ICollection<Student> Student { get; set; }
    }