Get the database backup using PHP - php

Question

following is the code I found over the internet to get the database backup using php. code works fine in the local host. but when it is in the online server, it does not works properly. it creates a database .sql file but the file is empty. what is the problem?? I think it is a server permission problem. how can I make this code works on my online server.??? :(
<?php
$con = mysqli_connect("localhost","root","","dhn_online_db");
$tables = array();
$query = mysqli_query($con, 'SHOW TABLES');
while($row = mysqli_fetch_row($query)){
$tables[] = $row[0];
}
$result = "";
foreach($tables as $table){
$query = mysqli_query($con, 'SELECT * FROM '.$table);
$num_fields = mysqli_num_fields($query);
$result .= 'DROP TABLE IF EXISTS '.$table.';';
$row2 = mysqli_fetch_row(mysqli_query($con, 'SHOW CREATE TABLE '.$table));
$result .= "\n\n".$row2[1].";\n\n";
for ($i = 0; $i < $num_fields; $i++) {
while($row = mysqli_fetch_row($query)){
$result .= 'INSERT INTO '.$table.' VALUES(';
for($j=0; $j<$num_fields; $j++){
$row[$j] = addslashes($row[$j]);
$row[$j] = str_replace("\n","\\n",$row[$j]);
if(isset($row[$j])){
$result .= '"'.$row[$j].'"' ;
}else{
$result .= '""';
}
if($j<($num_fields-1)){
$result .= ',';
}
}
$result .= ");\n";
}
}
$result .="\n\n";
}
//Create Folder
$folder = 'Backup_Files/';
if (!is_dir($folder))
mkdir($folder, 0777, true);
chmod($folder, 0777);
$date = date('m-d-Y');
$filename = $folder."db_backup_".$date;
echo $filename;
$handle = fopen($filename.'.sql','w+');
fwrite($handle,$result,0777);
fclose($handle);
?>

Answer 1

Why are you trying to reinvent the wheel ?
$folder = __DIR__ . DIRECTORY_SEPARATOR . 'Backup_Files/';
if (!is_dir($folder)){
mkdir($folder, 0777, true);
$date = date('m-d-Y');
exec("mysqldump --user=... --password=... --host=... DB_NAME > {$folder}db_backup_{$date}.sql");
}