EF4中多对多关系表模型

数据库中有这样的三张表，Artist，Album，ArtistAlbum

 

Artist和Album是多对多的关系，ArtistAlbum 是Artist和Album的关联表。ArtistAlbum 是双主键，除了Artist和Album表的ID外没有其他任何其他字段。

新建一个项目，添加一个ADO.NET Entity Data Model，在数据库中选择上面三张表：

 

EMD中并没有关联表ArtistAlbum并没有作为一个实体呈现在EDM中 

  下面的代码是向Artist和Album表添加新的数据和在model中查询Artist的Album以及Album所属的Artist

 代码

             using  (EFDemoEntities context  =   new  EFDemoEntities())
            {
                 //  add an artist with two albums
                var artist  =   new  Artist { ArtistName  =   " 徐悲鸿 "  };
                var album1  =   new  Album { AlbumName  =   " 八骏图 "  };
                var album2  =   new  Album { AlbumName  =   " 八丑图 "  };
                artist.Albums.Add(album1);
                artist.Albums.Add(album2);
                context.Artists.AddObject(artist);
                 //  add an album for two artists
                var artist1  =   new  Artist { ArtistName  =   " zjz "  };
                var artist2  =   new  Artist { ArtistName  =   " 张大千 "  };
                var album  =   new  Album { AlbumName  =   " 大虾图 "  };
                artist1.Albums.Add(album);
                artist2.Albums.Add(album);
                context.Albums.AddObject(album);
                context.SaveChanges();
            }

             using  (EFDemoEntities context  =   new  EFDemoEntities())
            {
                Console.WriteLine( " Artists and their albums... " );
                var artists  =  from a  in  context.Artists select a;
                 foreach  (var artist  in  artists)
                {
                    Console.WriteLine( " {0} " , artist.ArtistName);
                     foreach  (var album  in  artist.Albums)
                    {
                        Console.WriteLine( " \t{0} " , album.AlbumName);
                    }
                }
                Console.WriteLine( " \nAlbums and their artists... " );
                var albums  =  from a  in  context.Albums select a;
                 foreach  (var album  in  albums)
                {
                    Console.WriteLine( " {0} " , album.AlbumName);
                     foreach  (var artist  in  album.Artists)
                    {
                        Console.WriteLine( " \t{0} " , artist.ArtistName);
                    }
                }
            }

 

输出结果如下：