// @nuget: EntityFramework

​

using System;

using System.Data.Entity;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        // BulkInsert: Easy to customize

        using (var context = new EntityContext())

        {

            List<Class>  list = new List<Class>();

            for(int i = 0; i < 10; i++)

            {

                list.Add(new Class() { Name ="Class_" + i});

            }

            List<Student> slist = new List<Student>();

            for(int i = 0; i < 3; i++)

            {

                slist.Add(new Student() { Name ="Student_" + i});

            }

            context.Student.AddRange(slist);

            context.Class.AddRange(list);

            context.StudentClass.Add(new StudentClass() {

                StudentClassID = 1,

                StudentID = slist[0].StudentID,

                Student = slist[0],

                ClassID = list[0].ClassID,

                Class = list[0]

            });

            context.StudentClass.Add(new StudentClass() {

                StudentClassID = 1,

                StudentID = slist[0].StudentID,

                Student = slist[0],

                ClassID = list[3].ClassID,

                Class = list[3]

            });

            context.SaveChanges();

            var test = context.StudentClass.Where(b => b.StudentID == 1);

            var outerLeftJoin = context.Class.GroupJoin(

                test,

                c => c.ClassID,

                f => f.ClassID,

                (c, f) => c

            );

            FiddleHelper.WriteTable(context.Class.ToList());

            FiddleHelper.WriteTable(context.Student.ToList());

            FiddleHelper.WriteTable(context.StudentClass.ToList());

            FiddleHelper.WriteTable(outerLeftJoin);

        }

    }

​

    public class EntityContext : DbContext

    {

        public EntityContext() : base(FiddleHelper.GetConnectionStringSqlServer())

        {

​

        }

        public DbSet<Class> Class { get; set; }

        public DbSet<Student> Student { get; set; }

        public DbSet<StudentClass> StudentClass { get; set; }

    }

    public class Class

    {

        public int ClassID { get; set; }

        public string Name { get; set; }

        public ICollection<StudentClass> StudentClass { get; set; }

    }

    public class Student

    {

        public int StudentID { get; set; }

        public string Name { get; set; }

        public ICollection<StudentClass> StudentClass { get; set; }

    }

    public class StudentClass 

    { 

        public int StudentClassID { get; set; }

        public int StudentID { get; set; }

        public Student Student { get; set; }

        public int ClassID { get; set; }

        public Class Class { get; set; }

    }

}