i am downloading files from server using WinSCP.Is it possible to write a query to download a large database using mysql query? Or using any other method i have tried with this code but i am not able to get the whole database structure

<?php

              if(file_exists('backup_sql/my_backup.zip'))
               {

                unlink('backup_sql/my_backup.zip');
               }


               $tables='*';
              $host='MY HOST NAME';
              $user='MY_USERNAME';
              $pass='MYPASSWORD';
              $name='MY_DB_NAME';

                $link = mysql_connect($host,$user,$pass);
          mysql_select_db($name,$link);

          //get all of the tables
          if($tables == '*')
          {
            $tables = array();
            $result = mysql_query('SHOW TABLES');
            while($row = mysql_fetch_row($result))
            {
              $tables[] = $row[0];
            }
          }
          else
          {
            $tables = is_array($tables) ? $tables : explode(',',$tables);
          }
          $return='';
          //cycle through
          foreach($tables as $table)
          {
            $result = mysql_query('SELECT * FROM '.$table);
            $num_fields = mysql_num_fields($result);

            //$return.= 'DROP TABLE '.$table.';';
            $row2 = mysql_fetch_row(mysql_query('SHOW CREATE TABLE '.$table));
            $return.= "\n\n".$row2[1].";\n\n";

            for ($i = 0; $i < $num_fields; $i++) 
            {
              while($row = mysql_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";
          }



          $rand_var=time();
            $files_to_zip = array(
            "'backup_sql/db-backup-'.$rand_var.'.sql'",

          );

         $name = 'db-backup-'.$rand_var.'.sql';
$data = $return;



?>

any one please help me... thank you