<?php
/*
    table:------------
    CREATE TABLE IF NOT EXISTS `user_meta` (
      `id` int(11) NOT NULL AUTO_INCREMENT,
      `user_id` int(11) NOT NULL,
      `option_name` varchar(50) NOT NULL,
      `option_value` varchar(50) NOT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=7 ;

 // default insert -------------->
    INSERT INTO `user_meta` (`id`, `user_id`, `option_name`, `option_value`) VALUES (1, 1, 'name', 'Joe'),(2, 1, 'age', '28'),(3, 1, 'gender', 'male'),(4, 2, 'name', 'jane'),(5, 2, 'age', '26'),(6, 2, 'gender', 'female');
*/


ini_set('display_errors', 1);
error_reporting(1);
$mysql= new mysqli('localhost', 'root', 'root', 'test');

// new row values  ---------------->
$new_row=array(
        'name'=>'Donny',
        'age'=>'30',
        'gender'=>'male',
        'country'=>'us'
    );
$user_id='3';

// get old rows from DB ------------>
$old_rows=$mysql->query("SELECT user_id from user_meta where user_id='".$user_id."'");

// if there are no rows or "$old_rows->num_rows" row count is not equal to "" count for user id ----------------->
if( $old_rows->num_rows==0 || count($new_row)!=$old_rows->num_rows )
{
    // if current row count is not equal to new row count removing old rows from table -------------->
        if($old_rows->num_rows>0){
            $result=$mysql->query("DELETE from user_meta where user_id='".$user_id."'");
        }

        // inserting new rows ------------------>
        $qry= "INSERT INTO user_meta  (user_id,option_name,option_value)";
        foreach($new_row as $index=>$value){
                $values[]="'".$user_id."', '".$index."','".$value."'";
        }
        $qry .=' VALUES ('.implode('),(',$values).')';
        if($result=$mysql->query($qry)){
            echo 'inserted';
        }else{
            echo $mysql->error;
        }

// if rows are same update ------------->
}else{
        $qry .= "UPDATE `user_meta` SET option_value = CASE option_name";
            foreach($new_row as $index=>$value){
                $qry .= " WHEN '".$index."' THEN '".$value."'  ";
                $indexes[]=$index;
            }
        $qry .= "END WHERE  user_id ='".$user_id."'  AND `option_name` IN ( '".join($indexes,"','")."') ";
        if($result=$mysql->query($qry)){
            echo 'updated';
        }else{
            echo $mysql->error;
        }
}
?>