Mysql Edit

<?php
 
/*
CREATE TABLE  `addnew` (
 `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY ,
 `author` VARCHAR( 255 ) NOT NULL ,
 `title` VARCHAR( 255 ) NOT NULL ,
 `content` LONGTEXT NOT NULL
) ENGINE = MYISAM ;
*/
 
$connect = mysql_connect( 'localhost','root','0000' ) or die ( mysql_error() );
mysql_select_db( 'news' ) or die ( mysql_error() );
mysql_query("SET NAMES 'utf8'");
 
$gid = intval($_GET['id']);
$id = $_POST['id'];
$a = $_POST['author'];
$t = $_POST['title'];
$c = $_POST['content'];
 
if (isset($_POST['edit']) and $_POST['edit'] == 'news'  ) {
    $update = mysql_query("update addnew set 
    author='$a',
    title='$t',
    content='$c'
    where id='$id' ") or die ("Update failed");
 
    if (isset($update)) {
        echo "<h2>Update is Done</h2>";
    }
}
 
$query = mysql_query("select * from addnew where id ='".$gid."' ") or die("Mysql Error");
$re = mysql_fetch_assoc($query);
 
echo "
<form action='".$_SERVER["PHP_SELF"]."' method='post'>
Author : <input type='text' name='author' value='".$re['author']."' />
Title : <input type='text' name='title' value='".$re['title']."' /> <br/><br/>
Content : <textarea name='content'>".$re['content']."</textarea><br/> <br/>
<input type='submit' value='Save' />
<input type='hidden' name='id' value='".$gid."' />
<input type='hidden' name='edit' value='news' />
 
</form>
";
 
 
?>