PHP - Session

                      Session is the temporary memory to store a particular value. All of you use gmail, that gmail is the bset example for session concept. If you login gmail, then close the browser. Now you open gmail in your browser, you login gmail again. Unlike, you logout from gmail and close the browser. Now you can't login again. It comes to login page. This is the session concept. The value is stored in session until you destroy the session.

Session in php:

                      In php, there is 3 steps for session.
                      1. Start the session using session_start().
                      2. Load values to session variable by $_SESSION['name']='Guru'.
                      3. Destroy the session by session_destroy() or unset($_SESSION['name']).

session_start() in php:

                      It is used to start the session in php. Consider folowing example in php:

<?php    
         session_start();
         $_SESSION['name']='Guru';    
         echo $_SESSION['name'];
?>

                     Now you'll get output:     Guru

Suppose you run file without session_start(). Then you'll get error message like below:

session_destroy() in php: 

                   It is used to destroy the session. Consider following example in php:

welcome.php:

<?php    
         session_start();
         $_SESSION['name']='Guru';    
         echo $_SESSION['name'].'<br>';
         echo'<a href="signout.php">Signout</a>';
?>

signout.php:

<?php    
         session_start();
         session_destroy();
         header('location:welcome.php');
?>

                When you run the welcome.php, your output like this:

                       Guru
                       Signout

                  When you click the signout, it destroy the session and navigates to welcome.php. Now you try to clikc back button on your browser, it go to welcome.php page, but the value stored in session is not displayed. It give error message like below:

unset() in php:

                  You can also delete the session using unset() in php. The script for unset() as follows as:

<?php    
         session_start();
         unset($_SESSION['name']);
         header('location:welcome.php');
?>

It is also give same output like session_destroy() in php.

Related Post:

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How to store values in cookie using PHP
How to retrieve values from cookies in PHP
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How to store multiple values into session in PHP

Pagination using php and mysql with jquery and ajax

                      You can display values with pagination using php. But you have to pass the page number and also relevant values through url. So your url look like this:

                                   pagination.php?p=2

                      The good php website should be contain good url strucutre. Thats why you alter the urls using .htaccess. You don't need to show passing values in url. It can be hidden by .htaccess. If you don't know, just visit Redirect urls using htaccess. 
                      So you need ajax and jquery to pass the values. Already you know the basic pagination concept. Otherwise, please visit Pagination using php and mysql. 

 Pagination using juery and ajax:

                       You need small function which is called by onclick event to display values with pagination in php. The jquery function as follows as:

<script type="text/javascript">
   function page(e) {
         $.ajax({
                       url:'pagination.php',
                       data:{p:e},
                       dataType:'html',
                       Type:'post',
                       success:function(e) {
                          $('#page').html(e);
                           }
                      });
                  }
</script>

   
         Where,
                     - function page(e){} is called from click event.
        ie, <a onclick="return page('.$i.')">'.$i.'</a>            
                    
                     - e is a page number passed from click event.
                     - pagination.php is name of this php file.
                      You define the url, data, dataType and type in ajax post to pass the values.

The overall php script for pagination: 

<html>
<body>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<div id='page'>
<?php
error_reporting('E_ALL ^ E_NOTICE');
mysql_connect('localhost','root','') or die(mysql_error());
mysql_select_db('new') or die(mysql_error());
$page=$_REQUEST['p'];
$limit=10;
if($page=='')
{
 $page=1;
 $start=0;
}
else
{
 $start=$limit*($page-1);
}
$query=mysql_query("select * from table1 limit $start, $limit") or die(mysql_error());
$tot=mysql_query("select * from table1") or die(mysql_error());
$total=mysql_num_rows($tot);
$num_page=ceil($total/$limit);
echo'<table><th>Reg.Id</th><th>Name</th><th>Category</th>';
while($res=mysql_fetch_array($query))
{
  echo'<tr><td>'.$res['game_ID'].'</td><td>'.$res['game_Title'].'</td><td>'.$res['category_Name'].'</td></tr>';
}
echo'</table>';
function pagination($page,$num_page)
{
  echo'<ul style="list-style-type:none;">';
  for($i=1;$i<=$num_page;$i++)
  {
      if($i==$page)
      {
         echo'<li style="float:left;padding:3px;">'.$i.'</li>';
      }
        else
     {
       echo'<li style="float:left;margin-                 left:4px;background:rgb(170,177,35);padding:4px;cursor:pointer;border:1px solid darkgreen ;"><a  onclick="return page('.$i.')">'.$i.'</a></li>';
      }
   }
  echo'</ul>';
}
if($num_page>1)
{
 pagination($page,$num_page);
}
?>
<script type="text/javascript">
function page(e) {
$.ajax({
url:'pagination.php',
data:{p:e},
dataType:'html',
Type:'post',
success:function(e){
   $('#page').html(e);
  }
});
}
</script>
</div>
</body>

</html>

You'll get output like like this:

                     Now you can paginated to next page. The url structure of your website should be fine.

Note:
             For pagination, you need any jquery reference like:
" <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script> "

Related Post:

Sorting column by clicking column header using php and mysql
Sorting column with pagination by clicking column header using php and mysql

Sorting column with pagination by clicking column header using php and mysql

                       All of you know how to sorting column while clicking column header like mysql table in database through my previous post. Don't you know? Please visit this sorting column by clicking column header using php .

                       Now we are going to see about sorting column with pagination like table in mysql database. You sorting column by clicking column header in mysql table and you paginated to next page. You will get result followed by next value.
                       ie, you sort column by id. First 30 values displayed in first page in mysql table. When you paginate to next page, you will get output from 31st to 60 in your mysql table. Can you make your table like mysql table with sorting and pagination? Yes, you can also done pagination using php.
                      Already you know the sorting concepts. So now we will see sorting with pagination concepts.

                      1. Start and limit values based on page number:

$limit=10;
 $page=$_GET['p'];
 if($page=='')
 {
  $page=1;
  $start=0;
 }
 else
 {
  $start=$limit*($page-1);
 }

     Where,
                  $limit is the number rows per page.
                  $page is page number.
                  $start is starting point of limit in mysql query.

                    2. Total number of data in mysql table:
Then we need to calculate the total number of data in table. Then find the maximum pages like below:

$total_values=mysql_query("SELECT game_ID, category_Name, game_Title FROM table1");
$total=mysql_num_rows($total_values);
$maxpage=ceil($total/$limit);

     Where,
                mysql_num_rows() returns the numbers results in numeric.
                ceil() returns the whole digit number. ie, ceil(2.3) => 3.
                $maxpage returns the number of pages.

                     3. Function for pagination:

function pagination($maxpage,$page,$url,$field,$sort)
{  
  //After you sorting your table by clicking particular column, the following trick is used to display 
   //values with similar sorted values.
  if($sort=='ASC')
  {
    $sort='DESC';
  }
  else
  {
    $sort='ASC';
  }
  echo'<ul style="list-style-type:none;">';
   for($i=1; $i<=$maxpage; $i++)
   {
    if($i==$page)
{
 echo'<li style="float:left;padding:5px;">'.$i.'</li>';
}
else
{
 echo'<li style="float:left;padding:5px;"><a href="sort.php?p='.$i.'&sorting='.$sort.'&field='.$field.' ">'.$i.'</a></li>';
}
   }
  echo'</ul>';
}
pagination($maxpage,$page,$url,$field,$sort);

          Where, you have to use small tricks. You have to pass the sorting and field values in url using function.
ie, Already we set if the url get 'ASC' value, then it will take as 'DESC'. This is for sorting. Similarly, you have to do same thing for pagination.

Sorting column with pagination by clicking column header:

The total php script as follows for both sorting and pagination  by clicking column header:

<?php
error_reporting(E_ALL ^ E_NOTICE);
mysql_connect('localhost','root','') or die(mysql_error());
mysql_select_db('new');
$field='game_ID';
$sort='ASC';
if(isset($_GET['sorting']))
{
  if($_GET['sorting']=='ASC')
  {
  $sort='DESC';
  }
  else { $sort='ASC'; }
}
if($_GET['sorting'])
{
if($_GET['field']=='game_ID')
{  $field = "game_ID";  }
elseif($_GET['field']=='category_Name')
{ $field = "category_Name"; }
elseif($_GET['field']=='game_Title')
{ $field="game_Title"; }
}
//pagination
 $url='sort.php';
 $limit=10;
 $page=$_GET['p'];
 if($page=='')
 {
  $page=1;
  $start=0;
 }
 else
 {
  $start=$limit*($page-1);
 }

$sql = "SELECT game_ID, category_Name, game_Title FROM table1 ORDER BY $field $sort limit $start, $limit";
$total_values=mysql_query("SELECT game_ID, category_Name, game_Title FROM table1");
$total=mysql_num_rows($total_values);
$maxpage=ceil($total/$limit);
$result = mysql_query($sql) or die(mysql_error());
echo'<table border="0">';
echo'<th><a href="sort.php?sorting='.$sort.'&field=game_ID">Game Id</a></th>
     <th><a href="sort.php?sorting='.$sort.'&field=category_Name">Category Name</a></th>
<th><a href="sort.php?sorting='.$sort.'&field=game_Title">Game Name</a></th>';
while($row = mysql_fetch_array($result)) {
echo'<tr><td>'.$row['game_ID'].'</td><td>'.$row['category_Name'].'</td><td>'.$row['game_Title'].'</td></tr>';
}
echo'</table>';
function pagination($maxpage,$page,$url,$field,$sort)
{
  //After you sorting your table by clicking particular column, the following trick is used to display
   //values with similar sorted values.
  if($sort=='ASC')
  {
    $sort='DESC';
  }
  else
  {
    $sort='ASC';
  }
  echo'<ul style="list-style-type:none;">';
   for($i=1; $i<=$maxpage; $i++)
   {
    if($i==$page)
{
echo'<li style="float:left;padding:5px;">'.$i.'</li>';
}
else
{
echo'<li style="float:left;padding:5px;"><a href="sort.php?p='.$i.'&sorting='.$sort.'&field='.$field.' ">'.$i.'</a></li>';
}
   }
  echo'</ul>';
}
pagination($maxpage,$page,$url,$field,$sort);
?>

               Now you will get output  like this:

               Now you can sorting column with pagination by clicking column header.          

Related Post:

Simple pagination concepts using php and mysql
Pagination using php, mysql and ajax

Sorting column by clicking column header with php and mysql in table

                       All of you use the tables in mysql database. When you click the column header at first time, it displays values in ascending order. Likewise it displays values in descending order, while clicking field name second time. Normally the table look like this:

When you click the category_Name field, it display value by ascending order as follow as:

                      We can make our table like tables in mysql database. We can sorting values in column by clicking filed name. It can be done by PHP.
Follow the below steps.
          1. Connect file with mysql database as follows as:

mysql_connect('server_name','username','password');
mysql_select_db('db_name');

where,
           - server_name means localhost,
           - username is username of your database
           - password is password of your database
           - db_name is name of your database

         2. Then, you need to sorting tables based on column filed name. So you have to pass the field name in url. Similarly, you sort table values both ascending and descending. So you need to also pass order types in url. By default, table values displays in ascending. You can fixed order types and also field name.

$field='game_ID';
$sort='ASC';

where, the mysql table display values by ascending order based on game_ID

Now your headings should be like this.

<th><a href="table1.php?sorting='.$sort.'&field=game_ID">Game Id</a></th>
<th><a href="table1.php?sorting='.$sort.'&field=category_Name">Category Name</a></th>
<th><a href="table1.php?sorting='.$sort.'&field=game_Title">Game Name</a></th>

where,
           - table1.php is the name of file.
           - $sort means order type either ascending or descending
           - game_ID, category_Name, game_Title are field names in mysql table.

        3. Now you need get the values from url.

if(isset($_GET['sorting']))
{
  if($_GET['sorting']=='ASC')
  {
  $sort='DESC';
  }
  else { $sort='ASC'; }
}
if($_GET['field']=='game_ID')
{ 
    $field = "game_ID";  
}
elseif($_GET['field']=='category_Name')
{
   $field = "category_Name"; 
}
elseif($_GET['field']=='game_Title')
{ 
   $field="game_Title"; 
}

where, you handle your statergies. ie, If sorting value is ascending, then you will sort table by descending. Likewise you'll sort table by ascending, if sort value is descending. Then you need to get column field values.
           
       4. Then you write a query in which both order types and field name should be present. The mysql query should be like this.

SELECT game_ID, category_Name, game_Title FROM yobash_game ORDER BY $field $sort

where,
            - $filed is a default field name ie, gameId
            - $sort is a default order type already we fixed. ie. ASC

Sorting column by clicking column header

       5. Finally combine all the PHP codes as follows as:

table1.php

<?php
mysql_connect('localhost','root','') or die(mysql_error());
mysql_select_db('db_name') or die(mysql_error());
$field='game_ID';
$sort='ASC';
if(isset($_GET['sorting']))
{
  if($_GET['sorting']=='ASC')
  {
  $sort='DESC';
  }
  else
  {
    $sort='ASC';
  }
}
if($_GET['field']=='game_ID')
{
   $field = "game_ID";
}
elseif($_GET['field']=='category_Name')
{
   $field = "category_Name";
}
elseif($_GET['field']=='game_Title')
{
   $field="game_Title";
}
$sql = "SELECT game_ID, category_Name, game_Title FROM yobash_game ORDER BY $field $sort";
$result = mysql_query($sql) or die(mysql_error());
echo'<table border="1">';
echo'<th><a href="table1.php?sorting='.$sort.'&field=game_ID">Game Id</a></th>
     <th><a href="table1.php?sorting='.$sort.'&field=category_Name">Category Name</a></th>
<th><a href="table1.php?sorting='.$sort.'&field=game_Title">Game Name</a></th>';
while($row = mysql_fetch_array($result))
{
echo'<tr><td>'.$row['game_Id'].'</td><td>'.$row['category_Name'].'</td><td>'.$row['game_Title'].'</td></tr>';
}
echo'</table>';
?>

          Finally you'll get PHP scripts for sorting table when you click the column filed name. Now you can sort tables as like as tables in mysql database.

Related Post:
Simple pagination concepts using php and mysql
Pagination using php, mysql and ajax