<?php

$a= array( '1' => 'elem 1', '2'=> 'elem 2', '3'=>' elem 3');
print_r($a);
echo ("<br></br>");
$b=serialize($a);
print_r($b);

?>

Array ( [1] => elem 1 [2] => elem 2 [3] => elem 3 )

a:3:{i:1;s:6:"elem 1";i:2;s:6:"elem 2";i:3;s:7:" elem 3";}

Array ( [1] => elem 1 [2] => elem 2 [3] => elem 3 )

{ 1 : 'elem 1', 2 : 'elem 2', 3 : 'elem 3' }

a:3:{i:1;s:6:"elem 1";i:2;s:6:"elem 2";i:3;s:7:" elem 3";}

<array>
    <element key='1'>elem 1</element>
    <element key='2'>elem 2</element>
    <element key='3'>elem 3</element>
</array>

echo '<pre>';
// say you have an array something like this
$multidimentional_array= array(
    array(
        array("rose", 1.25, 15),
        array("daisy", 0.75, 25),
        array("orchid", 4, 7)
       ),
    array(
        array("rose", 1.25, 15),
        array("daisy", 0.75, 25),
        array("orchid", 5, 7)
       ),
    array(
        array("rose", 1.25, 15),
        array("daisy", 0.75, 25),
        array("orchid", 8, 7)
    )
);

// serialize
$serialized_array=serialize($multidimentional_array);
print_r($serialized_array);

a:3:{i:0;a:3:{i:0;a:3:{i:0;s:4:"rose";i:1;d:1.25;i:2;i:15;}i:1;a:3:{i:0;s:5:"daisy";i:1;d:0.75;i:2;i:25;}i:2;a:3:{i:0;s:6:"orchid";i:1;i:4;i:2;i:7;}}i:1;a:3:{i:0;a:3:{i:0;s:4:"rose";i:1;d:1.25;i:2;i:15;}i:1;a:3:{i:0;s:5:"daisy";i:1;d:0.75;i:2;i:25;}i:2;a:3:{i:0;s:6:"orchid";i:1;i:5;i:2;i:7;}}i:2;a:3:{i:0;a:3:{i:0;s:4:"rose";i:1;d:1.25;i:2;i:15;}i:1;a:3:{i:0;s:5:"daisy";i:1;d:0.75;i:2;i:25;}i:2;a:3:{i:0;s:6:"orchid";i:1;i:8;i:2;i:7;}}}

$original_array=unserialize($serialized_array);
var_export($original_array);

<?php
$a= array("1","2","3");
print_r($a);
$b=serialize($a);
echo $b;
$c=unserialize($b);
print_r($c);

a:3:{i:0;s:1:"1";i:1;s:1:"2";i:2;s:1:"3";}

$posts = base64_encode(serialize($_POST));
header("Location: $_SERVER[REQUEST_URI]?x=$posts");

if($_GET['x']) {
   // unpack serialize and encoded URL
   $_POST = unserialize(base64_decode($_GET['x']));
}

**Explain:**Create a table named history which stores all changes. Each time there is a change insert a new row in this table. It might have this fields:

  history(id,target_table(name of the table), target_id (ID of the saved entry),create/edit/change data (serialized data of the saved row),date)