Databases
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<?php
/**
* Class DB_Pager
*
* Class to build dynamic database paging links.
*
* Based upon Joao Prado Maia (jpm@musicalidade.net) class navbar.
*
* Functions:
* DB_Pager($use_text_links = true)
* build_links($option = 'all', $show_blank = false)
* build_url()
* display_links($sep_left = ' ', $sep_right = ' ')
* execute($sql, $db, $type = 'mysql')
* mk_link($href, $text = '', $target = '', $name = '')
* num_links_shown($links_to_show)
* rows_per_page($rows_to_show)
*
* @author Michael Cannon <michael@cannonbose.com>
* @package cb_common
* @version $Id: class.DB_Pager.php,v 1.5 2002/11/08 17:55:42 mcannon Exp $
*/
/**
Below is short example of how to use this class:
=============================================
<?php
// database connection stuff
$db = mysql_connect("localhost", "root", "");
mysql_select_db("DNAccounting", $db) or die(mysql_errno() . ': '
. mysql_error() . '<br />');
// create SQL statement WITHOUT LIMIT clause
$sql = "SELECT * FROM Reports ";
// including the DB_Pager class
include("./class.DB_Pager.php");
// initiate it!
$nav = new DB_Pager();
// the third parameter of execute() is optional
$result = $nav->execute($sql, $db, 'mysql');
// default link display
echo $nav->display_links();
echo "<hr>n";
// display result set
while ( $data = mysql_fetch_object($result) )
{
echo "$data->defrep_id : $data->service_id : $data->quantity<br />n";
}
?>
*/
class DB_Pager
{
// Default values for the navigation link bar
var $rows_per_page_default;
var $rows_per_page;
var $num_links_shown_default;
var $num_links_shown;
// navigation text
var $str_first;
var $str_previous;
var $str_next;
var $str_last;
// Variables used internally
var $file;
var $row;
var $total_records;
/**
* DB_Pager($use_text_links = true)
*
* Class constructor
*
* @param boolean $use_text_links, ex: true (display 'First, Previous, ...'),
* false (display '<<, <, ...')
* @return void
*/
function DB_Pager($use_text_links = true)
{
$this->rows_per_page_default = 15;
$this->rows_per_page = $this->rows_per_page_default;
$this->num_links_shown_default = 5;
$this->num_links_shown = $this->num_links_shown_default;
// Default values for the navigation link bar
if ( true === $use_text_links )
{
$this->str_first = '<b>First Page</b>';
$this->str_previous = '<b>Previous Page</b>';
$this->str_next = '<b>Next Page</b>';
$this->str_last = '<b>Last Page</b>';
}
else
{
$this->str_first = '<b><<</b>';
$this->str_previous = '<b><</b>';
$this->str_next = '<b>></b>';
$this->str_last = '<b>>></b>';
}
// Variables used internally
$this->file = '';
$this->row = 0;
$this->total_records = 0;
}
/**
* build_links($option = 'all', $show_blank = false)
*
* This function creates an array of all the links for the navigation bar.
* This is useful since it is completely independent from the layout or
* design of the page. The function returns the array of navigation links to
* the caller php script, so it can build the layout with the navigation
* links content available.
*
* @param string $option (default to 'all'), ex:
* 'all' - return every navigation link
* 'pages' - return only the page numbering links
* 'sides' - return only the 'Next' and / or 'Previous' links
* @param boolean $show_blank parameter (default to 'false'), ex:
* false - don't show the "Next" or "Previous" when it is not needed
* true - show the "Next" or "Previous" strings as plain text when it is
* not neededa
* @return array
*/
function build_links($option = 'all', $show_blank = false)
{
$extra_vars = $this->build_url();
$file = $this->file;
// zero based counting adjust
$number_of_pages = ceil($this->total_records / $this->rows_per_page);
$last_page = $number_of_pages - 1;
$indice = 0;
if ( $option == 'all' || $option == 'sides' )
{
// beginning link
// previous link
if ( $this->row != 0 )
{
$array[$indice] = $this->mk_link("{$file}?row=0{$extra_vars}",
$this->str_first);
$indice++;
$array[$indice] = $this->mk_link("{$file}?row=" . ($this->row - 1)
. $extra_vars, $this->str_previous);
$indice++;
}
elseif ( $this->row == 0 && $show_blank )
{
$array[$indice] = $this->str_first;
$indice++;
$array[$indice] = $this->str_previous;
$indice++;
}
}
// show all, some, or none of the page links
$this->num_links_shown = ( false !== $this->num_links_shown )
? $this->num_links_shown
: $last_page;
$row_diff = $this->row - $this->num_links_shown;
$from_link = ( $row_diff < 0 )
? 0
: $row_diff;
$row_sum = $this->row + $this->num_links_shown;
$to_link = ( $row_sum > $number_of_pages )
? $number_of_pages
: $row_sum;
for ($current = $from_link; $current <= $to_link; $current++)
{
// current link
// other page links
if ( ( $option == 'all' || $option == 'pages' )
&& $current <= $last_page )
{
$array[$indice] = ( $this->row != $current )
? $this->mk_link("{$file}?row={$current}{$extra_vars}",
$current + 1)
: $current + 1;
}
// next link
if ( ( $option == 'all' || $option == 'sides' )
&& $current == $to_link )
{
if ( ( $this->row != $to_link || $from_link == $to_link )
&& $this->row != $last_page )
{
$array[$indice] = $this->mk_link("{$file}?row="
. ($this->row + 1) . $extra_vars, $this->str_next);
}
elseif ( ( $this->row == $to_link || $this->row == $last_page )
&& $show_blank )
{
$array[$indice] = $this->str_next;
}
}
$indice++;
}
if ( $option == 'all' || $option == 'sides' )
{
// ending link
if ($this->row != $last_page)
{
$array[$indice] = $this->mk_link("{$file}?row="
. $last_page . $extra_vars, $this->str_last);
}
elseif ( ($this->row == $last_page) && $show_blank )
{
$array[$indice] = $this->str_last;
}
}
return $array;
}
/**
* build_url()
*
* This function creates a string that is going to be added to the url string
* for the navigation links. This is specially important to have dynamic
* links, so if you want to add extra options to the queries, the class is
* going to add it to the navigation links dynamically.
*
* @return string
*/
function build_url()
{
global $REQUEST_URI;
global $REQUEST_METHOD;
global $HTTP_GET_VARS;
global $HTTP_POST_VARS;
$query_string = '';
list($fullfile, $voided) = explode("?", $REQUEST_URI);
$this->file = $fullfile;
$cgi = $REQUEST_METHOD == 'GET' ? $HTTP_GET_VARS : $HTTP_POST_VARS;
reset ($cgi);
while (list($key, $value) = each($cgi)) {
if ($key != "row")
$query_string .= "&" . $key . "=" . $value;
}
return $query_string;
}
/**
* display_links($sep_left = ' ', $sep_right = ' ')
*
* Simple format and return as string of build_links().
*
* @param string $sep_left left side separator, ex: ' ', ' ['
* @param string $sep_right right side separator, ex: ' ', ' ]'
* @return string
*/
function display_links($sep_left = ' ', $sep_right = '')
{
$string = '';
$links = $this->build_links();
// reindex links
$links = array_values($links);
foreach ( $links AS $key => $value )
{
// middle stuff
// last item
if ( 0 != $key )
{
$string .= $sep_left . $value . $sep_right;
}
// first item
else
{
$string .= ( '' == $sep_right )
? $value
: $sep_left . $value . $sep_right;
}
}
return $string;
}
/**
* execute($sql, $db, $type = 'mysql')
*
* The next function runs the needed queries. It needs to run the first time
* to get the total number of rows returned, and the second one to get the
* limited number of rows.
*
* @param string $sql parameter actual SQL query to be performed
* @param resource $db database link identifier
* @param string $type database type parameter, ex:
* 'mysql' - uses mysql php functions
* 'pgsql' - uses pgsql php functions
* @return resource
*/
function execute($sql, $db, $type = 'mysql')
{
global $row;
$this->row = $row;
$start = $this->row * $this->rows_per_page;
if ($type == 'mysql')
{
$result = mysql_query($sql, $db);
$this->total_records = mysql_num_rows($result);
$sql .= " LIMIT $start, $this->rows_per_page";
$result = mysql_query($sql, $db);
}
elseif ($type == 'pgsql')
{
$result = pg_Exec($db, $sql);
$this->total_records = pg_NumRows($result);
$sql .= " LIMIT $this->rows_per_page, $start";
$result = pg_Exec($db, $sql);
}
return $result;
}
/**
* mk_link($href, $text = '', $target = '', $name = '')
*
* Create an HTML link.
*
* @param string $href relative, absolute, or other kind of link,
* ex: 'a.php', 'http://cannonbose.com'
* @param string $text link text to display, ex: 'Home'
* @param string $target page target, ex: '_blank', '_parent'
* @param string $name link name, ex: 'top', 'Barry_Manilow'
* @return string
*/
function mk_link($href, $text = '', $target = '', $name = '')
{
$out = '<a';
$out .= ( '' != $name ) ? " name='$name'" : '';
$out .= ( '' != $href ) ? " href='$href'" : '';
$out .= ( '' != $target ) ? " target='$target'" : '';
$out .= '>';
$out .= ( '' != $text ) ? $text : $href;
$out .= '</a>';
return $out;
}
/**
* num_links_shown($links_to_show)
*
* Helper function to set var $num_links_shown. Checks for numbers less than
* zero and defaults var $num_links_shown if so.
*
* @param integer $links_to_show, ex: 10, 50
* @return void
*/
function num_links_shown($links_to_show)
{
$this->num_links_shown = (0 < $links_to_show || false == $links_to_show)
? $links_to_show
: $this->num_links_shown_default;
}
/**
* rows_per_page($rows_to_show)
*
* Helper function to set var $row_per_page. Checks for numbers less than
* zero and defaults var $row_per_page if so.
*
* @param integer $rows_to_show, ex: 10, 50
* @return void
*/
function rows_per_page($rows_to_show)
{
$this->rows_per_page = ( 0 < $rows_to_show )
? $rows_to_show
: $this->rows_per_page_default;
}
}
?>
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Usage Example
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<?php
error_reporting(E_ALL);
// database connection stuff
$db = mysql_connect("localhost", "root", "");
// $db = mysql_connect("localhost", "root", "");
mysql_select_db("DNAccounting", $db) or die(mysql_errno() . ': '
. mysql_error() . '<br />');
$sql = "SELECT * FROM Reports ";
// including the DB_Pager class
// include("./class.DB_Pager.php");
// initiate it!
$nav = new DB_Pager();
// set how many records to show at a time
if ( isset($show) )
{
$nav->rows_per_page($show);
}
$nav->str_first = 'Alpha';
$nav->str_last = 'Omega';
// the third parameter of execute() is optional
$result = $nav->execute($sql, $db);
// build the returned array of navigation links
$links = $nav->build_links();
$links = array_values($links);
// display links
for ($y = 0; $y < count($links); $y++) {
echo ' ' . $links[$y] . ' ';
}
echo '<hr />';
// handle the returned result set
while ( $data = mysql_fetch_object($result) )
{
echo "$data->defrep_id : $data->service_id : $data->quantity<br />n";
}
echo "<hr>n";
// default link display
// semi-, ala- Google
echo $nav->display_links();
echo "<hr>n";
// "piped" link display
echo $nav->display_links(' | ');
echo "<hr>n";
// "blocked" link display
echo $nav->display_links(' [', ']');
?>
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