有错误：

致命错误：无法在第10行的/home/XXXX/public_html/XXXXX/install/include/database.php中重新声明类MYSQLi_DB

和database.php文件：

<?php

        date_default_timezone_set("Asia/Tehran");
if (file_exists(dirname(__FILE__)."/constant.php")) {
    include(dirname(__FILE__)."/constant.php");
} else {
    die('Cant find constant.php in /install/include/database.php');
}

class MYSQLi_DB {

    var $connection;

    function MYSQLi_DB () {
        $this->connection = mysqli_connect(SQL_SERVER, SQL_USER, SQL_PASS, SQL_DB) or die(mysqli_error());
    }
        function query($query) {
        return $this->connection->query($query);
        }

};

class MYSQL_DB {

    var $connection;

    function MYSQL_DB() {
        $this->connection = mysql_connect(SQL_SERVER, SQL_USER, SQL_PASS) or die(mysql_error());
        mysql_select_db(SQL_DB, $this->connection) or die(mysql_error());
        mysql_set_charset('utf8');
    }

    function mysql_exec_batch ($p_query, $p_transaction_safe = true) {
  if ($p_transaction_safe) {
      $p_query = 'START TRANSACTION;' . $p_query . '; COMMIT;';
    };
  $query_split = preg_split ("/[;]+/", $p_query);
  foreach ($query_split as $command_line) {
    $command_line = trim($command_line);
    if ($command_line != '') {
      $query_result = mysql_query($command_line);
      if ($query_result == 0) {
        break;
      };
    };
  };
  return $query_result;
} 

    function query($query) {
        return mysql_query($query, $this->connection);
    }
};

if(DB_TYPE) {
    $database = new MYSQLi_DB;
}
else {
    $database = new MYSQL_DB;
}
?>

这个类（MYSQLi_DB）没有调用任何其他地方！就在这个文件中......你能帮我解决一下吗？

php fatal-error redeclare