Updating timestamp

Parvenu

I've set up my forum, and the table structure is as follows:
one table for topics (f1_topics), and one for replies (f1_replies)
f1_topics consits of:
author, title, body, posted, modified, timestamp, postid, replyid
f1_replies consists of:
author, title, body, posted, modified, timestamp, replyid, topicid

In each case, topicid and replyid link to the topic associated with the reply and the last reply posted, respectively. The other fields, I think, are self-explanatory.

What I want to do is:
When a new reply is posted, update the timestamp in the topics table with the timestamp of the most recent reply related to that topic. How would I go about doing that? If I used "UPDATE f1_topics SET timestamp", I'm guessing that wouldn't work. Seeing as it's an automatically updated field, would it need a value passed?
Also, would "SORT BY timestamp" sort the entries correctly, according to the time posted?

Help would be appreciated...

mogster

Think you're right, the timestamp will update itself when the other fields are updated.
And you can sort by timestamp, and use DESC if you like a reverse sort.

knutm

Parvenu

Sorry, what I meant was update the timestamp field in the topics table with the value from the last reply... basically, when it saves the reply in f1_replies, to also update the timestamp in topics with the timestamp in replies so that it sends it to the top when a reply is posted.
I'm sure it can't be very complicated, I just can't see how to do it

Parvenu

I really need an answer, my forum won't work properly 'til I have this sorted.
I was thinking perhaps I could amalgamate date figures in to one long number, so for example 4:30pm on February 27th 2003 would be 200302271630... this would sort it correctly wouldn't it?

mogster

If you're gonna update the timestamp manually, don't use timestamp at all. I just use a standard unix time, generated by time(). If you create a field int(20), then generate
$thisTime = time();
and inserts it on post/update, it should do the trick.
The unix stamp may be displayed as anything by the date()-function:
http://www.php.net/manual/en/function.date.php

knutm