wired problem...

stezz

hey.. i've built a forum that displays 5 results per page... this is the code...

if(!$start) {
		$start = 0;
	}

$limit = 5;

$result = mysql_query("SELECT * FROM newrepublic_mbs WHERE parent_id = '$PID' ORDER BY PID LIMIT $start, $limit;");

if($start >= $limit) {
	$start = $start-$limit;
	echo "<a href=\"$PHP_SELF?action=read&BID=$BID&PID=$PID&start=$start\"><< Previous</a>";
}

if($countpr > ($start + $limit) ) {
	$start = $start+$limit;
	echo "<a href=\"$PHP_SELF?action=read&BID=$BID&PID=$PID&start=$start\">Next >></a>";
}

$countpr is the number of replies for the given topic ($PID)... there are 6 replies in total, so the "next" link appears and when clicked, it displays the remaining 1 reply. But the next link is still being displayed when there are no more replies for that topic. Why is this?

Thanks, Stezz.

terfle

Did you do an echo to see if the variables were being passed/created like you thought? Like this:

echo "countpr: " . $countpr . "<BR>";
echo "start: ". $start . "<BR>";
echo "limit:" $limit . "<BR>";

stezz

Ok, I did what you said and for some reason, it says that the start value is 0 even when it's equal to 5. This is the function in it's entirety...

function check_replies($PID) {
	global $PID, $start, $BID;

if(!$start) {
	$start = 0;
}

$limit = 5;

$result = mysql_query("SELECT * FROM newrepublic_mbs WHERE parent_id = '$PID' ORDER BY PID LIMIT $start, $limit;");
if(mysql_num_rows($result)) {

	while($r = mysql_fetch_array($result)) {

		$reply_user = mysql_query("SELECT * FROM newrepublic_members WHERE ID = '$r[posted_by]';");
		$ru = mysql_fetch_array($reply_user);

		$countposts = mysql_query("SELECT Count(*) FROM newrepublic_mbs WHERE posted_by = '$r[posted_by]';");
		$cp = mysql_fetch_array($countposts);

		$countpr = $cp[0];

		$countreplies = mysql_query("SELECT Count(*) FROM newrepublic_mbs WHERE parent_id = '$PID';");
		$cr = mysql_fetch_array($countreplies);

		$count_re = $cr[0];

		$rank = mysql_query("SELECT * FROM newrepublic_ranks WHERE RID = '$ru[rank]';");
		$ra = mysql_fetch_array($rank);

		$format_time = strftime("%d/%m/%y at %H:%M", $r[timestamp]);

		$message = nl2br($r[message]);

		echo "<table class=\"newsitem\">";
		echo "<tr align=\"center\" class=\"newsitemhead\"><td colspan=2>Author<br></td><td colspan=2>Thread<br></td></tr>";
		echo "<tr valign=\"top\"><td width=25% colspan=2 class=\"newsitembody\"><b>Reply By</b>:<br> <a href=\"profile.php?mode=member&MID=$ru[ID]\">$ra[rankabb]]|[$ru[username]</a><br><b>Location</b>:<br> $ru[location]<br><b>Posts</b>:<br> $countpr<br><br></td>";
		echo "<td colspan=2 class=\"newsitembottom\"><b>Subject</b>: $r[subject] &nbsp;&nbsp; <b>Date</b>: $format_time<br><hr align=\"center\" width=90%><br>$message<br><br></td></tr>";
		echo "</table><br>";

	}

} else {

	echo "This message has no replies.";

}

if($start >= $limit) {
	$start = $start-$limit;
	echo "<a href=\"$PHP_SELF?action=read&BID=$BID&PID=$PID&start=$start\"><< Previous</a>";
}

echo "Number of Replies: " . $count_re . "<BR>";
echo "Limit: " . $limit . "<BR>";
echo "Start Value: " . $start;

if($start+$limit < $count_re) {
	$start = $start+$limit;
	echo "<a href=\"$PHP_SELF?action=read&BID=$BID&PID=$PID&start=$start\">Next >></a>";
}

}

Please help, I don't understand why it won't accept the start value.

Thanks, Stezz.

Weedpacket

Originally posted by stezz
Please help, I don't understand why it won't accept the start value.

Have a look at the URL of the Next>> link when you click on it - see what the value of start is there. And have a look at Question One of the Newbies Forum FAQ; following what is said there can save a lot of this sort of hassle.

stezz

It still doesn't make any sense because $start is the only variable that is empty... the rest have values such as $BID and $PID and they're both pulled from the URL. Why should $start be any different?

bubblenut

What's the exact URL being called?

stezz

Before the next link is clicked...

http://www.newrepublic.be/~slackerworld/forums.php?action=read&BID=1&PID=13

once the next link has been click once (so $start has increased by 5)....

http://www.newrepublic.be/~slackerworld/forums.php?action=read&BID=1&PID=13&start=5

However, once the link has been clicked to reveal the URL above, the next link still appears eventhough there are only 2 posts on that page. When you hover the mouse over the next link the value of $start is still 5.

Doesn't make any sense.

Stezz.

Weedpacket

Why are you passing $PID as a parameter and as a global? One or the other, please. Preferably a parameter, globals should be avoided if you can feasibly do so: for all anyone can tell, some other function is messing with the global $start value and setting it to zero. You'll have to dig through all the functions that use it and see what they do and work out whether or not they might be getting called before you get to check_replies().

If you had been accessing your form variables properly a test like if(!$start) $start=0 would be unnecessary (if that's there for the reason I think it is, then it's poor programming practice. Coding with error reporting set to E_ALL will probably make your script spew notices in all directions).

Your calculation of $count_re can be taken out of the loop, and put before where you set $result. In fact, you'd have to, because otherwise if there were no more replies, $count_re wouldn't be set and your use of it later would give bogus results (and trigger more notices).

And finally, if you are on the second page and decide you need to display a <<Previous link, you also change the value of $start. And it's the altered value of $start (i.e., the start of the previous page) you test and use when you try to decide whether to show a Next>> link. A bit more debugging, a few more echoes checking the values of various variables, would have revealed this if an eyeball inspection of the program's logic didn't.