PHP Paging With Custom Pagesize

[cancer10]

Hello,

I was going through this tutorial:
http://www.php-mysql-tutorial.com/php-mysql-paging.php

And noticed this line:

$rowsPerPage = 20;

Here, we are defining the Rows per page in the code itself. I was wondering, if I allow my visitors to set this value from the webpage itself, what bugs would that carry in my code (assuming I am using the exact code in the link above)?

Thanx

[simshaun]

None, just make sure its an integer (whole number) and >= 1.

Also make sure you filter it in the query using mysql_real_escape_string so you don't risk getting hacked (easily).

[galen]

None, just make sure its an integer (whole number) and >= 1.

Also make sure you filter it in the query using mysql_real_escape_string so you don't risk getting hacked (easily).

better yet use a prepared query

[simshaun]

You are assuming the query will never change?

What about if you need to implement joins, change what columns you select, change sort orders... etc?

[Jake Arkinstall]

You are assuming the query will never change?

Makes no difference - a query can be modified in PDO as much as it could in MySQL.

[simshaun]

Hmm. either I am misunderstanding or I'm stupid.

Prepared query being prepared in sql or prepared query as in using pdo to escape values for you?

[cancer10]

Makes no difference - a query can be modified in PDO as much as it could in MySQL.

What is a PDO?


Thanx

[Raju Gautam]

I was wondering, if I allow my visitors to set this value from the webpage itself, what bugs would that carry in my code (assuming I am using the exact code in the link above)?

Nothing will happen. You just track the user selected value like this:

if(isset($_GET['perpage'])){
   $rowsPerPage = $_GET['perpage'];
}
else{
    $rowsPerPage = 20;
} 

What is a PDO?

http://www.php.net/pdo

[cancer10]

The reason why I asked u this question was, I currently have 8 records in my DB. The navigation/Pagination works fine if my customer enters any value in the PageSize textbox except the value 1, 6 and 7.

1) If they enter the value 1 in the PageSize textbox then the nav pagination loops from 0 to 7. Clicking on the [7th] hyperlink, gives a record not found error.

2) If they enter the value 6, then the page displays only 6 rows. (Not sure why)

3) If they enter the value 7, then the the page displays only 7 rows. (Not sure why)

For the remaining values, it displays all the 8 records. Which is fine.

Any idea why is this happening?

Thanx

[simshaun]

I think that shows that the pagination is coded wrong.

[cancer10]

I m using this code

http://www.php-mysql-tutorial.com/php-mysql-paging.php

[jim9]

I have found that this generic paging function works no matter if mysql, mysqli, or pdo:

<?php
function pager($numpages, $page, $self, $limit, $queryvars = '')
{
$maxPage = ceil($numpages / $limit);
echo "whitaker ===".$maxPage."===".$page."===".$self."===".$queryvars;
echo "maxpage ==== ".$maxPage;
if ($maxPage > 5)
{

$spage = $page;
$epage = $page + 4;
	$spage = $page;
	$epage = $page + 4;
	$menu7 = '';
	if($page != 1)
	{
	$menu7 .= '<a href="'.$self.'?page='.($page - 1).'&'.$queryvars.' ">&lt;&lt; PREV </a>';
	}
	if ($epage < $maxPage)
		{
		for ($i = $spage; $i <= $epage; $i++)
		{
		if ($i == $page)
		{
		$menu7 .= '<class="selected">'.$i.'';
		}
		else
		{
		$menu7 .= '<a href="'.$self.'?page='.$i.'&'.$queryvars.'">'.$i.'</a>'."\n";
		}
		}
		}
	else
		{
		 for ($i = $spage; $i <= $maxPage; $i++)
		{
		if ($i == $page)
		{
		$menu7 .= '<class="selected">'.$i.'';
		}
		else
		{
		$menu7 .= '<a href="'.$self.'?page='.$i.'&'.$queryvars.'">'.$i.'</a>'."\n";
		} //bottom else
		} //for
		} //top else
	if ($page < $maxPage) 
	{
	$menu7 .= '<a href="'.$self.'?page='.($page + 1).'&'.$queryvars.'"> NEXT &gt;&gt;</a>';
	}
}
else
{
	$menu7 = '';
	if($page != 1)
	{
	$menu7 .= '<a href="'.$self.'?page='.($page - 1).'&'.$queryvars.'">&lt;&lt; PREV </a>';
	}
	for ($i = 1; $i <= $maxPage; $i++)
	{
	if ($i == $page)
	{
	$menu7 .= '<class="selected">'.$i.'';
	}
	else
	{
	$menu7 .= '<a href="'.$self.'?page='.$i.'&'.$queryvars.'">'.$i.'</a>'."\n";
	}
	}
	if ($page < $maxPage) 
	{
	$menu7 .= '<a href="'.$self.'?page='.($page + 1).'&'.$queryvars.'"> NEXT &gt;&gt;</a>';
	}

}
return $menu7;
}
?>

It's called like this:

$menu = '';
$menu = pager($_SESSION['total_records'], $page, $self, $limit, $queryvars );

queryvars would be something for the querystring like

$queryvars = "lname=$lname";