상속: DbContext
 public string deleteComment(int CommentID)
 {
     try
     {
         using (var ctx = new CommentContext())
         {
             Comment oldComment = ctx.Comments.Find(CommentID);
             if (oldComment != null)
             {
                 ctx.Comments.Remove(oldComment);
                 ctx.SaveChanges();
             }
         }
         return "ok";
     }
     catch (Exception)
     {
         return "fail";
     }
 }
 public string updateComment(int CommentID, string CommentText)
 {
     try
     {
         using (var ctx = new CommentContext())
         {
             Comment oldComment = ctx.Comments.Find(CommentID);
             if (oldComment != null)
             {
                 oldComment.CommentText = CommentText;
                 ctx.SaveChanges();
             }
         }
         return "ok";
     }
     catch (Exception)
     {
         return "fail";
     }
 }
        public string createComment(string Comment, int PostID)
        {
            try
            {
                using (var ctx = new CommentContext())
                {
                    Comment comment = new Comment()
                    {

                        CommentText = Comment,
                        PostID = PostID,
                        CommentDate = new DateTime()
                    };
                    ctx.Comments.Add(comment);
                    ctx.SaveChanges();
                }
                return "ok";
            }
            catch (Exception)
            {
                return "fail";
            }
        }