Threaded Forum

[mrchimp]

Hello everyone

 

I'm trying to make a threaded forum, where each reply sits below the item it was a reply to....(like slashdot.org or b3ta.com.

Problem is I can't figure out a neat way of doing this that doesn't involve one SQL query per item.

My brain's stuck in an infinite loop on this one, can anyone help?

 

Thans in advance!

[premiso]

Post some code/SQL if you want help.

[mrchimp]

I've only got pseudocode at the moment, but so far i've got something like....

 

posts database:

id, datetime, replyto, userid, content

1, 13/01/2009, NULL, 1, "blah blah blah"

2, 13/01/2009, NULL, 1, "kjhsad"

3, 14/01/2009, 1, 1, "asd asd asd"

 

which i'd like to display as

POST 1

    POST 3(reply to post 1)

POST 2 (new post)

 

 

So far i'm looking at something like....

SELECT * FROM posts WHERE replyto = NULL

foreach{
     echo "content id=1"
     ifexists (posts entry with replyto=1)
          echo "content id=2"
          if exists(posts entry with replyto=2)
          etc....
}

 

But it's getting this bit to loop nicely that I'm having problems with.

I had naively hope to be able to use some kind of recursive function like

 

writePost(){
   echo "post content"
   if (reply exists){
      writePost($replyid);
   }
}

 

but that doesn't appear to be an option and it also involves an SQL query for each entry, which seems a bit excessive.

[premiso]

The kicker is without your table structure it is hard to really help.

 

It would go something like this, you have a thread table. In this you have a parentid set where if this is not 0 then the thread is a reply. You would then send a parent/threadid if that is present you query selecting all rows where parentid is equal to what you sent you would have an OR statement here to OR threadid = passed parent id. Then you would order it by threadid which should put the threads in order, oldest showing first and so on.

 

All done with 1 query.

[mrchimp]

my table structure is up there ^^

i've called it posts, you've called it threads...i've called it replyto, you've called it parentid.

 

What you've said makes sense, but surely that would only work with one depth? I mean if i have post #1, then post #2 with parentid=1 would both be picked, but if there's a post #3 with parentid=2 that wuoldn't be shown

[premiso]

my table structure is up there ^^

i've called it posts, you've called it threads...i've called it replyto, you've called it parentid.

 

What you've said makes sense, but surely that would only work with one depth? I mean if i have post #1, then post #2 with parentid=1 would both be picked, but if there's a post #3 with parentid=2 that wuoldn't be shown

 

Ah you are talking about actually linking a reply to a reply. You would need a recursive function for that if I am not mistaken, and it would be multiple queries in that case. You could, however, is have a"replyto" and a "originalid" then put the original ID and pull out by that then sort by threadid, replytoid  and that should work.

[mrchimp]

Thanks for that.

 

If anyone else is having trouble with this I'd recommend this article