How should I seed data to many to many relation in Entity Framework Code first 5.0

Question

I am having my first steps in EF 5.0 I have a many to many relationship. Movie can Have multiple Types and Type can have multiple Movies

public class Movie
{
            


        

Answer 1

You need a joining table to implement a many-to-many relationship.

For example, think of a scenario where students can enroll in multiple courses and a course can have mutiple students.

Class structure would look like,

class Course
{  
  public int Id { get; set; }
  public string Name { get; set; }

}

class Student
{  
  public int Id { get; set; }
  public string Name { get; set; }

}

class CourseStudent
{  
  public int Id { get; set; }
  public int CourseId { get; set; }
  public int StudentId { get; set; }
  public Course Course { get; set; }
  public Student Student { get; set; }
}

To seed data, just create instances of the CourseStudent class and AddOrUpdate on the DbSet.

    var course1 = new Course { Name = "course1" };
    var course2 = new Course { Name = "course2" };

    var student1 = new Student { Name = "student1" };
    var student2 = new Student { Name = "student2" };

context.CourseStudents.AddOrUpdate(r => r.Id,
                new CourseStudent { Course = course1, Student = student1 },
                new CourseStudent { Course = course1, Student = student2 },
                new CourseStudent { Course = course2, Student = student1 },
                new CourseStudent { Course = course2, Student = student2 });

Answer 2

Just create a few movies and a few types and create relationships by adding some of those types to the Movie.Types collection (or the other way around), for example:

protected override void Seed(MyContext context)
{
    var movie1 = new Movie { Name = "A", Types = new List<Type>() };
    var movie2 = new Movie { Name = "B", Types = new List<Type>() };
    var movie3 = new Movie { Name = "C", Types = new List<Type>() };

    var type1 = new Type { MovieType = "X" };
    var type2 = new Type { MovieType = "Y" };

    movie1.Types.Add(type1);

    movie2.Types.Add(type1);
    movie2.Types.Add(type2);

    movie3.Types.Add(type2);

    context.Movies.Add(movie1);
    context.Movies.Add(movie2);
    context.Movies.Add(movie3);
}