Non incremental MySQL backup script

<?php
/***************************************************************************
 *   copyright: (C) 2008 Sawyerr Ken
 *   developer site: http://www.sawyerrken.net/
 *   description: non-incremental mysql database backup script
 *   written: Feb 2008
 ***************************************************************************/

/***************************************************************************
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version. Although none of the code may be
 *   sold. If you have been sold this script, get a refund.
 ***************************************************************************/
//change the  variables here to fit your connection settings
$host = "";
$username = "";
$password = "";
$database = "";


//do not change anything from here
function backup_tables($host,$user,$pass,$name,$tables = '*')
{

  $link = mysqli_connect($host,$user,$pass);
  mysqli_select_db($link,$name);
  if($tables == '*')
  {
    $tables = array();
    $result = mysqli_query($link,'SHOW TABLES');
    while($row = mysqli_fetch_row($result))
    {
      $tables[] = $row[0];
    }
  }
  else
  {
    $tables = is_array($tables) ? $tables : explode(',',$tables);
  }
  foreach($tables as $table)
  {
    $result = mysqli_query($link,'SELECT * FROM '.$table);
    $num_fields = @mysqli_num_fields($result);

    $return.= 'DROP TABLE '.$table.';';
    $row2 = @mysqli_fetch_row(mysqli_query($link,'SHOW CREATE TABLE '.$table));
    $return.= "\n\n".$row2[1].";\n\n";

    for ($i = 0; $i < $num_fields; $i++)
    {
      while($row = mysqli_fetch_row($result))
      {
        $return.= 'INSERT INTO '.$table.' VALUES(';
        for($j=0; $j<$num_fields; $j++)
        {
          $row[$j] = addslashes($row[$j]);
          $row[$j] = ereg_replace("\n","\\n",$row[$j]);
          if (isset($row[$j])) { $return.= '"'.$row[$j].'"' ; } else { $return.= '""'; }
          if ($j<($num_fields-1)) { $return.= ','; }
        }
        $return.= ");\n";
      }
    }
    $return.="\n\n\n";
  }
$time=date("Y-m-d:H:i:s");
  $handle = fopen('../../hourly_backups/db-backup-'.$time.'-'.$name.'.sql','w+');
  fwrite($handle,$return);
  fclose($handle);
}


backup_tables($host,$username,$password,$database);
?>