Next and Previous Links using Functions

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September 5th, 2006, 05:04 PM

cybernine

Join Date: Apr 2007

Posts: 73

Time spent in forums: < 1 sec
Reputation Power: 2

Next and Previous Links using Functions

I have been working on this for a while, trying to simplify previous and next links using functions. So here it is, Please let me know how it works for you.

Basic Rundown

This script can pull information from MySQL Database and let you use Previous and Next Links to navigate. All you have to do is set the configuration info at the top of the script and setup the SELECT statement and the rows. This also works well using include from another php file.

UPDATED 09/11/2006 6:12

Removed gpageNum function and added it in with recordPaging().
Fixed problem with results with only 2 pages.
Added Comments
Updated Record Paging
Added Not displaying links when its not needed.

php Code:

Original - php Code

<?php
// MySQL Host Name or IP Address, Default 'localhost'
$sql_host = 'localhost';
// MySQL Username, Default 'root'
$sql_usr = 'root';
// MySQL Password.
$sql_pass = '';
// MySQL Database to use
$sql_db = 'employees';
// How many rows to return in a page.
$paging_maxrows = 15;
// Default page number to start from, Default left '0'.
$paging_pagenum = 0;
// Alternate's row color in a result 1st row.
$rowColor1 = "FFFFFF";
// Alternate's row color in a result 2st row.
$rowColor2 = "#00CCCC";
/*Page Title Name*/
$strPageTitle = 'Next & Previous Links';
/*Domain Name: Example http://www.google.com*/
$homeURL = "http://www.google.com";

/*NO MORE CONFIGURATION REQUIRED AFTER THIS POINT*/

// Gets the current full url page location.
// This function forces a user go to the full URL.
function currentPage() {
global $homeURL;

$currentpage = sprintf("%s%s", $homeURL, $_SERVER["PHP_SELF"]);
return $currentpage;

}

// Queries a MySQL Database
function dbquery($strSQL) {
global $sql_host, $sql_usr, $sql_pass, $sql_db;

$db = mysql_connect($sql_host, $sql_usr,$sql_pass);
	mysql_select_db($sql_db,$db);
	
	if (!$queryValue = @mysql_query($strSQL, $db)) {
	die("<p><font color='red'>Error: ".mysql_error())."</p>";
	} Else {	
	return $queryValue;
	}	}

// Queries a MySQL Database and allows paging results.
// Insert the UPDATE, SELECT, OR DELETE statement where $strSQL is using the function.
function dbqueryl($strSQL) {
global $sql_host, $sql_usr, $sql_pass, $sql_db, $paging_maxrows, $paging_pagenum;

$db = mysql_connect($sql_host, $sql_usr, $sql_pass);
mysql_select_db($sql_db, $db);

// Returns the current pageNumber or defaults to page '0'.
$pagenum = 0;
if (isset($_GET['pageNumber'])) {
  $pagenum = $_GET['pageNumber'];
}
$startRow = $pagenum * $paging_maxrows;

// Inserts the LIMIT statement in the $strSQL statement.
$query_limit = sprintf("%s LIMIT %d, %d", $strSQL, $startRow, $paging_maxrows);
	if (!$queryValue = mysql_query($query_limit, $db)) {
	die("<p><font color='red'>Error: ".mysql_error())."</p>";
	} Else {	
	return $queryValue;
}	
}

// Alternates the row color in a result.
function rowColor() {
global $rowColor1, $rowColor2, $ity0;

if($ity0 % 2) {
print $rowColor1;
} else { 
print $rowColor2;
} 
$ity0++;
}

// Recordset Paging that is used with function "dbqueryl".
function recordPaging($sql) {
global $paging_maxrows, $paging_pagenum, $currentPage;

$sel_pagenum_sql = dbquery($sql);
$sel_pagenum = mysql_num_rows($sel_pagenum_sql);
$page_number = ceil($sel_pagenum/$paging_maxrows)-1;

// Function to replace the pageNumber and TotalPages in the Query String
if(isset($_GET['pageNumber'])) {
$current_pagenum = $_GET['pageNumber'];
} else {
$current_pagenum = 0;
}

if(isset($_GET['TotalPages'])) {
$current_totalpages = $_GET['TotalPages'];
} else {
$current_totalpages = 0;
}

$url_querystr = $_SERVER['QUERY_STRING']; // Gets the current query string
$find_page_info = sprintf("pageNumber=%d&TotalPages=%d&", $current_pagenum, $current_totalpages);
$rem_page_info = str_replace($find_page_info, '', $url_querystr);
$alt = $rem_page_info;
// End of Function to replace the pageNumber and TotalPages in the Query String

echo "<table width="360" border="0" align="center">n";
echo "<tr class="tblrow">n";
// First Page Link.
echo "<td width="90" align="center">n";
if($current_pagenum > 0) { // If Page 0, Do not display First Page Link.
printf ("<a href="%s?pageNumber=%d&TotalPages=%d&%s">First Page </a>n", currentPage(), 0, $page_number, $alt);
}
echo "</td>n";
// Previous Page Link.
echo "<td width="90" align="center">n";
if($current_pagenum > 0) { // If Page 0, Do not display Previous Link.
$previous = max(0, $current_pagenum - 1);
printf ("<a href="%s?pageNumber=%d&TotalPages=%d&%s">Previous Page</a>n", currentPage(), $previous, $page_number, $alt);
}
echo "</td>n";
// Next Page Link.
echo "<td width="90" align="center">n";
if($current_pagenum != $page_number) { // If Page is Last, Do not display Next Page Link.
$next = min($page_number, $current_pagenum + 1);
printf ("<a href="%s?pageNumber=%d&TotalPages=%d&%s">Next Page</a>n", currentPage(), $next, $page_number, $alt);
}
echo "</td>n";
// Last Page Link.
echo "<td width="90" align="center">n";
if($current_pagenum != $page_number) { // If Page is Last, Do not display Last Page Link.
printf ("<a href="%s?pageNumber=%d&TotalPages=%d&%s">Last Page</a>n", currentPage(), $page_number, $page_number, $alt);
echo "</td>n";
}
echo "</tr>n";
echo "</table>n";

}

?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title><?php echo $strPageTitle; ?></title>
</head>

<body>
<p>
  <?php
$Search_Search = "0";
if (isset($_GET['Search'])) {
  $Search_Search = $_GET['Search'];
}

$Search_sql = "SELECT * FROM employees";
$Search = dbqueryl($Search_sql);

while ($row = mysql_fetch_assoc($Search)) {
print "".$row['Name']."<br >";

}
?>
</p>
<?php recordPaging($Search_sql); // Reference the SQL statement inside the () to caculate the correct pages to result. ?>
</body>
</html>

 
<?php
// MySQL Host Name or IP Address, Default 'localhost'
$sql_host = 'localhost';
// MySQL Username, Default 'root'
$sql_usr = 'root';
// MySQL Password.
$sql_pass = '';
// MySQL Database to use
$sql_db = 'employees';
// How many rows to return in a page.
$paging_maxrows = 15;
// Default page number to start from, Default left '0'.
$paging_pagenum = 0;
// Alternate's row color in a result 1st row.
$rowColor1 = "FFFFFF";
// Alternate's row color in a result 2st row.
$rowColor2 = "#00CCCC";
/*Page Title Name*/
$strPageTitle = 'Next & Previous Links';
/*Domain Name: Example http://www.google.com*/
$homeURL = "http://www.google.com";
 
 
/*NO MORE CONFIGURATION REQUIRED AFTER THIS POINT*/
 
 
 
 
// Gets the current full url page location.
// This function forces a user go to the full URL.
function currentPage() {
global $homeURL;
 
$currentpage = sprintf("%s%s", $homeURL, $_SERVER["PHP_SELF"]);
return $currentpage;
 
}
 
// Queries a MySQL Database
function dbquery($strSQL) {
global $sql_host, $sql_usr, $sql_pass, $sql_db;
 
    $db = mysql_connect($sql_host, $sql_usr,$sql_pass);
    mysql_select_db($sql_db,$db);
    
    if (!$queryValue = @mysql_query($strSQL, $db)) {
    die("<p><font color='red'>Error: ".mysql_error())."</p>";
    } Else {    
    return $queryValue;
    }   }
 
// Queries a MySQL Database and allows paging results.
// Insert the UPDATE, SELECT, OR DELETE statement where $strSQL is using the function.
function dbqueryl($strSQL) {
global $sql_host, $sql_usr, $sql_pass, $sql_db, $paging_maxrows, $paging_pagenum;
 
$db = mysql_connect($sql_host, $sql_usr, $sql_pass);
mysql_select_db($sql_db, $db);
 
// Returns the current pageNumber or defaults to page '0'.
$pagenum = 0;
if (isset($_GET['pageNumber'])) {
  $pagenum = $_GET['pageNumber'];
}
$startRow = $pagenum * $paging_maxrows;
 
 
// Inserts the LIMIT statement in the $strSQL statement.
$query_limit = sprintf("%s LIMIT %d, %d", $strSQL, $startRow, $paging_maxrows);
    if (!$queryValue = mysql_query($query_limit, $db)) {
    die("<p><font color='red'>Error: ".mysql_error())."</p>";
    } Else {    
    return $queryValue;
}   
}
 
 
// Alternates the row color in a result.
function rowColor() {
global $rowColor1, $rowColor2, $ity0;
 
if($ity0 % 2) {
print $rowColor1;
} else { 
print $rowColor2;
} 
$ity0++;
}
 
 
// Recordset Paging that is used with function "dbqueryl".
function recordPaging($sql) {
global $paging_maxrows, $paging_pagenum, $currentPage;
 
 
$sel_pagenum_sql = dbquery($sql);
$sel_pagenum = mysql_num_rows($sel_pagenum_sql);
$page_number = ceil($sel_pagenum/$paging_maxrows)-1;
 
 
// Function to replace the pageNumber and TotalPages in the Query String
if(isset($_GET['pageNumber'])) {
$current_pagenum = $_GET['pageNumber'];
} else {
$current_pagenum = 0;
}
 
if(isset($_GET['TotalPages'])) {
$current_totalpages = $_GET['TotalPages'];
} else {
$current_totalpages = 0;
}
 
 
$url_querystr = $_SERVER['QUERY_STRING']; // Gets the current query string
$find_page_info = sprintf("pageNumber=%d&TotalPages=%d&", $current_pagenum, $current_totalpages);
$rem_page_info = str_replace($find_page_info, '', $url_querystr);
$alt = $rem_page_info;
// End of Function to replace the pageNumber and TotalPages in the Query String
 
 
 
echo "<table width="360" border="0" align="center">n";
echo "<tr class="tblrow">n";
// First Page Link.
echo "<td width="90" align="center">n";
if($current_pagenum > 0) { // If Page 0, Do not display First Page Link.
printf ("<a href="%s?pageNumber=%d&TotalPages=%d&%s">First Page </a>n", currentPage(), 0, $page_number, $alt);
}
echo "</td>n";
// Previous Page Link.
echo "<td width="90" align="center">n";
if($current_pagenum > 0) { // If Page 0, Do not display Previous Link.
$previous = max(0, $current_pagenum - 1);
printf ("<a href="%s?pageNumber=%d&TotalPages=%d&%s">Previous Page</a>n", currentPage(), $previous, $page_number, $alt);
}
echo "</td>n";
// Next Page Link.
echo "<td width="90" align="center">n";
if($current_pagenum != $page_number) { // If Page is Last, Do not display Next Page Link.
$next = min($page_number, $current_pagenum + 1);
printf ("<a href="%s?pageNumber=%d&TotalPages=%d&%s">Next Page</a>n", currentPage(), $next, $page_number, $alt);
}
echo "</td>n";
// Last Page Link.
echo "<td width="90" align="center">n";
if($current_pagenum != $page_number) { // If Page is Last, Do not display Last Page Link.
printf ("<a href="%s?pageNumber=%d&TotalPages=%d&%s">Last Page</a>n", currentPage(), $page_number, $page_number, $alt);
echo "</td>n";
}
echo "</tr>n";
echo "</table>n";
 
 
}
 
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title><?php echo $strPageTitle; ?></title>
</head>
 
<body>
<p>
  <?php
$Search_Search = "0";
if (isset($_GET['Search'])) {
  $Search_Search = $_GET['Search'];
}
 
$Search_sql = "SELECT * FROM employees";
$Search = dbqueryl($Search_sql);
 
 
while ($row = mysql_fetch_assoc($Search)) {
print "".$row['Name']."<br >";
 
}
?>
</p>
<?php recordPaging($Search_sql); // Reference the SQL statement inside the () to caculate the correct pages to result. ?>
</body>
</html>

September 6th, 2006, 07:36 AM

notepad

Join Date: Apr 2007

Location: Central, IL USA

Posts: 3,214

Time spent in forums: < 1 sec
Reputation Power: 5

RE: Next and Previous Links using Functions

not bad.. i think there is room for improvement. specifically:
- you might want to make sure that your query string for what page you're on doesn't interfere with any other query string variables..
- you might consider displaying page numbers, allowing people to jump 2 or 3 pages ahead, rather than forcing them to go one page at a time. or allow the developer to choose between several different displays. either way don't force the developer into using a table, try style sheets.
- don't link back to the page you're currently viewing
- i think you should allow the functions to be portable with both databases as well as flat-files.

some commenting in your code would be nice too.

September 6th, 2006, 01:23 PM

cybernine

Join Date: Apr 2007

Posts: 73

Time spent in forums: < 1 sec
Reputation Power: 2

RE: Next and Previous Links using Functions

I thought about several of those improvement options that you mentioned right after I posted this. I will be adding to this code soon. I just wanted people to have a better option of using next and previous links than what is posted in the tutorial section.

I am also open for any additional code that anyone might think will be usefull.