Code First（一）

1. public class Blog{ … public virtural ICollection<Post> Posts{get;set;}}
public class Post{… public ICollection<Comment> Comments{get;set;}}
public class Comment{… public Post Post{get;set;}}

2. public class BlogContext: DbContext
    {
         public DbSet<Blog> Blogs{get;set;}
         public DbSet<Post> Post{get;set;}
         public DbSet<Comment> Comment{get;set;}
    }

Database First（二）