Code First 中的 TPH TPT TPC

      public class Blog
      {
            public int Id { get; set; }
            public DateTime Creationdate { get; set; }
            public string ShortDescription { get; set; }
            public string Title { get; set; }
            public string AboutTheAuthor { get; set; }
      }

      public class PictureBlog : Blog
      {
            public string PicDescription { get; set; }
      }

      public class VideoBlog : Blog
      {
            public string VideoDescription { get; set; }
      }