<?php
require_once('wp-config.php');

//Attempt 1: Via command-line
/*
$backupFile = './art-ice-db-' . date("Y-m-d-H-i-s") . '.gz';
$command = "mysqldump --opt -h DB_HOST -u DB_USER -p DB_PASSWORD DB_NAME | gzip > $backupFile";
system($command, $ret);

echo $ret;
*/

//Attempt 2: Via PHP connecting to mysql
backup_tables(DB_HOST,DB_USER,DB_PASSWORD,DB_NAME);


/* backup the db OR just a table */
function backup_tables($host,$user,$pass,$name,$tables = '*')
{
  
  $link = mysql_connect($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);
  }
  
  //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";
  }
  
  //save file
  $handle = fopen('art-ice-db-backup-'.time().'-'.(md5(implode(',',$tables))).'.sql','w+');
  fwrite($handle,$return);
  fclose($handle);
}

Attempt 1 is a command-line attempt. Likely not to work due to php often running as "nobody". Attempt 2 is a php way, going through teach table in the database and writing out to a file.

Database dump using PHP

PHP