Question

I have a social networking website and I’m getting some difficulties to filter who can see the updates users post.

As in Facebook, I see all posts from my friends, even if I didn’t post anything.
I have these tables:

DiaryPosts table:

--------------------------------------
| ID | UserID | Content | UpdateTime |
--------------------------------------

Friends table:

--------------------------
| ID | UserID | FriendID |
--------------------------

Followers table:

----------------------------
| ID | UserID | FollowerID |
----------------------------

And I have this query that now it can’t filter anything:

var diaryPosts = (from d in db.DiaryPosts
                  orderby d.ID descending
                  select new DiaryPostsSet
                  {
                      PostID = d.ID,
                      Author = db.User.Where(m => m.ID == d.UserID).FirstOrDefault().Nickname,
                      Thumbnail = db.User.Where(m => m.ID == d.UserID).FirstOrDefault().Thumbnail,
                      AuthorComment = d.Content, 
                      UserID = d.UserID,
                      Time = d.UpdateTime }).Take(6).ToList();

I tried to write a where clause but it didn’t work.
Do you have any suggestions on how to write this query?

Answer 1

The answer is:

//queries for diary Posts
        var myDiaryPosts = (from d in db.DiaryPosts
                              join e in db.EstadosDeAlma
                              on d.EstadosDeAlmaID equals e.ID
                              join u in db.User
                              on d.UserID equals u.ID
                              where d.UserID == userset.ID
                              select new DiaryPostsSet { 
                                  PostID = d.ID,
                                  EstadoDeAlmaID = e.ID,
                                  EstadoDeAlma = e.Title,
                                  Author = u.Nickname,
                                  Thumbnail = u.Thumbnail,
                                  UserID = u.ID,
                                  IsDuplicated = d.IsDuplicated,
                                  FriendID = d.FriendID,
                                  FriendName = u.Nickname,
                                  Time = d.UpdateTime,
                                  MessagesCount = d.FriendMessages.Count(m => m.DiaryPostsID == d.ID)
                              });

        var friendsPosts = (from d in db.DiaryPosts
                               join e in db.EstadosDeAlma
                               on d.EstadosDeAlmaID equals e.ID
                               join fr in db.Friends
                               on d.UserID equals fr.FriendID
                               where fr.UserID == userset.ID
                               join u in db.User
                               on fr.FriendID equals u.ID
                               select new DiaryPostsSet
                               {
                                   PostID = d.ID,
                                   EstadoDeAlmaID = e.ID,
                                   EstadoDeAlma = e.Title,
                                   Author = u.Nickname,
                                   Thumbnail = u.Thumbnail,
                                   UserID = u.ID,
                                   IsDuplicated = d.IsDuplicated,
                                   FriendID = d.FriendID,
                                   FriendName = u.Nickname,
                                   Time = d.UpdateTime,
                                   MessagesCount = d.FriendMessages.Count(m => m.DiaryPostsID == d.ID)
                               });

        var followingsPosts = (from d in db.DiaryPosts
                                 join e in db.EstadosDeAlma
                                 on d.EstadosDeAlmaID equals e.ID
                                 join fl in db.Followers
                                 on d.UserID equals fl.UserID
                                 where fl.FollowerID == userset.ID
                                 join u in db.User
                                 on fl.UserID equals u.ID
                                 select new DiaryPostsSet
                                 {
                                     PostID = d.ID,
                                     EstadoDeAlmaID = e.ID,
                                     EstadoDeAlma = e.Title,
                                     Author = u.Nickname,
                                     Thumbnail = u.Thumbnail,
                                     UserID = u.ID,
                                     IsDuplicated = d.IsDuplicated,
                                     FriendID = d.FriendID,
                                     FriendName = u.Nickname,
                                     Time = d.UpdateTime,
                                     MessagesCount = d.FriendMessages.Count(m => m.DiaryPostsID == d.ID)
                                 });

        var diaryPosts = myDiaryPosts.Union(friendsPosts).Union(followingsPosts).OrderByDescending(d => d.Time).Take(6).ToList();