Pagination Problem

[sonal]

Thanks for the great book.

Now, I'm a newbee to PHP and trying to learn pagination concept. I got another problem. I am trying to list out books from database, on page by page. The first page shows perfect result (list of 5 books), with navigation buttons. When I click 2 (or any next page), the script throws an error.. saying, undefined variable dbc. If it gets "dbc" variable for the first 5 records, how come it becomes undefined for next pages?

Here is my code:

 

<?php #Script 1.6 - view_books.php

 

//This script retrieves all books from the books table.

//This version paginates the results.

 

$page_title = 'View all books';

 

require_once('../includes/configuration.inc.php');

 

include('../includes/headpart.html');

 

echo '<h1>Books List</h1>';

 

//Number of records to show per page.

 

$display = 5;

 

//Determine how many pages are there...

 

if(isset($_GET['p']) && is_numeric($_GET['p']))

{

//Already been determined.

 

$pages = $_GET['p'];

 

}

else { //Need to be determine.

 

require_once(MYSQL);

 

//count the number of records:

 

$q = "SELECT COUNT(bookid) FROM books";

 

$r = @mysqli_query($dbc, $q);

 

$row = @mysqli_fetch_array($r, MYSQLI_NUM);

 

$records = $row[0];

 

 

//calculate the number of pages..

 

if($records > $display)

{ //More than one page.

 

$pages = ceil($records/$display);

 

}

else {

$pages = 1;

}

} //End of p IF.

 

//Determine where in the database to start returning results...

 

if(isset($_GET['s']) && is_numeric($_GET['s']))

{

$start = $_GET['s'];

} else {

$start = 0;

}

 

//Make the query.

 

$q = "SELECT bookid, title, author, price, category FROM books order by title ASC LIMIT $start, $display";

 

$r = @mysqli_query($dbc, $q);

 

//Table header:

 

echo '<table align="center" cellspacing="0" cellpadding="5" width="75%">

<tr>

<td align="left"><b>Title</b></td>

<td align="left"><b>Author</b></td>

<td align="left"><b>Price</b></td>

<td align="left"><b>Category</b></td>

</tr>';

 

//Fetch and print all records:

 

$bg = '#eeeeee'; //set the initial background color.

 

if(mysqli_num_rows($r) > 0 )

{

while($row = mysqli_fetch_array($r, MYSQLI_ASSOC))

{

$bg = ($bg=='#eeeeee' ? '#ffffff' : '#eeeeee'); //Switch the background color.

 

echo '<tr bgcolor="' . $bg .'">

<td align="left">' . $row['title'] . '</td>

<td align="left">' . $row['author'] . '</td>

<td align="left">' . $row['price'] . '</td>

<td align="left">' . $row['category'] . '</td>

</tr>';

 

}

} //End of while loop.

echo '</table>';

 

mysqli_free_result($r);

mysqli_close($dbc);

 

//Make the links to other pages, if necessary.

 

if($pages > 1)

{

//Add some spacing and start a paragraph.

 

echo '<br /><p>';

 

//Determine what page the script is on:

 

$current_page = ($start/$display) + 1;

 

//IF it is not the first page, make a previous button:

 

if($current_page != 1)

{

echo '<a href="view_books.php?s=' . ($start - $display) . '&p=' . $pages . '"> Previous</a>';

}

 

//Make all the numbered pages.

 

for($i = 1; $i <= $pages; $i++)

{

if($i != $current_page)

{

echo '<a href="view_books.php?s=' . (($display * ($i - 1))) . '&p=' . $pages . '">' . $i . '</a>';

}

else {

echo $i . ' ';

}

} //End of for loop.

 

//If it's not the last page, make a next button.

 

if($current_page != $pages)

{

echo '<a href="view_books.php?s=' . ($start + $display) . '&p=' . $pages . '">Next</a>';

}

 

echo '</p>';

}

?>

[HartleySan]

Do you get an error when you click "Previous" or "Next"?