PHP stores and extracts time

In PHP, we can use time() function to store time in UNIX time in MySQL  and use date function to display time in a format such as date, month and year.
Example code:
<?php
$time=time();
echo $time.'<br />';
$date=date('l,jS,M,Y', $time);
echo $date;
?>
output:
1361774216
Monday,25th,Feb,2013

In this example we store $time as 1361774216 unix time and convert to date as:
Monday,25th,Feb,2013