php计算连接的mysql数据库的大小，用MB，KB或者GB的格式返回

function CalcFullDatabaseSize($database, $db) {          $tables = mysql_list_tables($database, $db);      if (!$tables) { return -1; }          $table_count = mysql_num_rows($tables);      $size = 0;          for ($i=0; $i < $table_count; $i++) {          $tname = mysql_tablename($tables, $i);          $r = mysql_query("SHOW TABLE STATUS FROM ".$database." LIKE '".$tname."'");          $data = mysql_fetch_array($r);          $size += ($data['Index_length'] + $data['Data_length']);      };          $units = array(' B', ' KB', ' MB', ' GB', ' TB');      for ($i = 0; $size > 1024; $i++) { $size /= 1024; }      return round($size, 2).$units[$i];  }        /*  ** Example:  */      // open mysql connection:  $handle = mysql_connect('localhost', 'user', 'password');      if (!$handle) { die('Connection failed!'); }      // get the size of all tables in this database:  print CalcFullDatabaseSize('customer1234', $handle);  // --> returns something like: 484.2 KB      // close connection:  mysql_close($handle);