php operates on the basic class code of the mysql database

<?php
$dbhost='localhost';
$dbuser='root';
$dbpass='123456';
$dbname='products';
$connect=mysql_connect($dbhost,$dbuser,$dbpass);
if(!$connect) exit(' Database connection failed! ');
mysql_select_db($dbname,$connect);
mysql_query('set names utf8');
// The query 
$sql="SELECT * FROM `category`";
$result=mysql_query($sql);
while($row=mysql_fetch_array($result)){
 echo $row['id'];
}
// insert 
$sql="INSERT INTO `category` (`id`,`name`) VALUES (NULL,'".$name."')";
$result=mysql_query($sql);
if(mysql_affected_rows()){
 echo ' Insert successful, insert ID To: ',mysql_insert_id();
}else{
 echo ' Insert failed: ',mysql_error();
}
// Modify the 
$sql="UPDATE `category` SET `name`='".$name."' WHERE `id`='".$id."'";
$result=mysql_query($sql);
if(mysql_affected_rows()){
 echo ' Modification successful! ';
}
// delete 
$sql="DELETE FROM `category` WHERE `id`='".$id."'";
$result=mysql_query($sql);
if(mysql_affected_rows()){
 echo ' Delete successful! ';
}
// Close the connection 
mysql_close($connect);
?>