Problem with rows and download

fr600

Hi guys,

I'm currently working with a download script and please take a look at this code...

$sql = "SELECT url FROM dl_url";
$result = mysql_query($sql);
$rows = mysql_num_rows($result);
for ($x=0;$x>$rows;$x++) {
$urlx[$x] = mysql_result($result,$x);
}
$request = $urlx[$download_id];

The problem is whenever no of rows on this table is lesser than download_id, the download won't start. For say, there are 2 entries on this table, and if an id is higher than 2, downlaod doesn't start but if it's 2 or 1 it does. So what i want is to use higher values for id and download would work. Like, id is 5026 and yet there are 2 entries on the table, it will still download. Can you guys help me with this, please 🙁 ??

laserlight

 $rows = mysql_num_rows($result);
for ($x=0;$x>$rows;$x++)

Now, we expect $rows to contain some non-negative integer.
The smallest non-negative integer is 0.
0 > 0 is false, so the loop does not run when $rows is 0.
But 0 > 1 is also false, as 0 > n is false when n >= 0, which is the case for all non-negative integers.
Conclusion: your for loop is never run.

fr600

Originally posted by laserlight
 $rows = mysql_num_rows($result);
for ($x=0;$x>$rows;$x++)
Now, we expect $rows to contain some non-negative integer.
The smallest non-negative integer is 0.
0 > 0 is false, so the loop does not run when $rows is 0.
But 0 > 1 is also false, as 0 > n is false when n >= 0, which is the case for all non-negative integers.
Conclusion: your for loop is never run. [/B]

Ohh, I see. But can you pleeeease tell me, in details if possible, how I can get what I'm looking for? 😕

Thnx for your help.

laserlight

But can you pleeeease tell me, in details if possible, how I can get what I'm looking for?

Well, for that we'll need to know what exactly are you trying to do.

fr600

I need to know how I can make the download work even if the download_id is higher than no. of rows in the table. 🙁

laserlight

I need to know how I can make the download work even if the download_id is higher that no. of rows.

Let's say there are n rows in the table, and download_id is n+1
$urlx cannot possibly have a numeric index greater than n-1
Even if the for loop works, it is impossible for your code to accept a download_id greater than (or even equal to) the number of rows.

What do you do then?
You need to provide an overview of what you are trying to do.
Not about the code that you're trying to fix, but about the problem that you're trying to solve.

fr600

I'm sorry I'm just a beginner and I don't know everything about PHP 🙁

laserlight

Um, you just need to know what problem you're trying to solve, and describe it clearly.

If you can, write the smallest and simplest script that demonstrates this problem.

fr600

Well let me give you an example...

In a table dl_url there are 3 entries
ID url
1 http://www.domain.com/file1.zip
2 http://www.domain.com/file2.zip
3 http://www.domain.com/file3.zip

So the download link here in my script is:
http://www.domain.com/download.php?id=1
Whenever I visit that link, it downlaods file1.zip

Now I if I change the id 1 to.. let's say 99, the entry in dl_url looks like:
ID url
99 http://www.domain.com/file1.zip

So the new download link is:
http://www.domain.com/download.php?id=99
Now when I visit this link, it doesn't download anything.

This is the code I've used:

$sql = "SELECT url FROM dl_url";
$result = mysql_query($sql);
$rows = mysql_num_rows($result);
for ($x=0;$x>$rows;$x++) {
$urlx[$x] = mysql_result($result,$x);
}
$request = $urlx[$download_id];

Now I want to know how I can make this link work:
http://www.domain.com/download.php?id=99

laserlight

Dont change the ID - it should be used as the primary key.

That said, this could be what you're after:

if (isset($_GET['id']) && ctype_digit($_GET['id'])) {
	$sql = "SELECT url FROM dl_url WHERE id='{$_GET['id']}'";
	$result = mysql_query($sql)
		OR die(mysql_error()); //for debugging
	//$result should contain a single field
	if (mysql_num_rows($result) == 1) {
		//$result should contain a single field in a single row
		$request = mysql_result($result, 0);
		//now $request has the URL requested
	} else {
		//invalid id specified - does not exist in table url_id
	}
} else {
	//id not specified or invalid
}

The idea is that you only need to select a single row - the one that the user requests based on id.

fr600

Thank you very very much. You saved my life...