Entity Framework mapping of 3 tables with relationship between each other

Question

Here's my problem: I have 3 tables in my database

1. Movies (list of movies)

   • ID
   • OriginalTitle ...

2. Genres (table with all possible genres)

   • ID
   • Name

3. RelatedGenres (those genres that belog to a specific movie and point a specific genre, since movie can have more than 1 genre)

   • ID
   • MovieID
   • GenreID

The relationships are as folows:

Movies.ID -> RelatedGenres.MovieID -> Genres.ID

I have a model with assosiations (navigation properties). What I get:

class Movie
{
   public int ID { get; set; }
   public string OriginalTitle { get; set; }
   public ObjectCollection<RelatedGenre> RelatedGenres { get; set; }
}

where

class RelatedGenre
{
   public int ID { get; set; }
   public int MovieID { get; set; }
   public ObjectCollection<Genre> Genres { get; set; }
}

What I want:

class Movie
{
   public int ID { get; set; }
   public string OriginalTitle { get; set; }
   public ObjectCollection<Genre> Genres { get; set; }
}

As you can see, i want to skip data from this array of RelatedGenres & just get array of concrete Genres...

How can I achive this? Thanks in advance =)

Answer 1

You need to remove th ID column of the RelatedGenres table. The join table of many-to-many relationship should only contain the keys of the participating entities.

EF will automatically model the relationship as you have shown in the final code sample.