DB::useDB PHP Method

    public static function useDB()
    {
        $args = func_get_args();
        return call_user_func_array(array(DB::getMDB(), 'useDB'), $args);
    }

function do_backup()
{
    if ($_POST['xsrf_token'] != $_SESSION['xsrf_token']) {
        trigger_error('XSRF code incorrect', E_USER_ERROR);
    }
    // By David Walsh
    $return = 'CREATE DATABASE `lhsmath-bak` DEFAULT CHARACTER SET latin1 COLLATE latin1_swedish_ci;' . "\n" . 'USE `lhsmath-bak`;' . "\n\n\n";
    $tables = array();
    $result = DB::queryRaw('SHOW TABLES');
    while ($row = mysqli_fetch_row($result)) {
        $tables[] = $row[0];
    }
    foreach ($tables as $table) {
        $result = DB::queryRaw('SELECT * FROM ' . $table);
        $num_fields = mysqli_num_fields($result);
        $return .= 'DROP TABLE IF EXISTS ' . $table . ';';
        $row2 = mysqli_fetch_row(DB::queryRaw('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] = str_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";
    }
    // LMT, also
    global $DB_DATABASE, $LMT_DB_DATABASE;
    DB::useDB($LMT_DB_DATABASE);
    $return .= 'CREATE DATABASE `lmt-bak` DEFAULT CHARACTER SET latin1 COLLATE latin1_swedish_ci;' . "\n" . 'USE `lmt-bak`;' . "\n\n\n";
    $tables = array();
    $result = DB::queryRaw('SHOW TABLES');
    while ($row = mysqli_fetch_row($result)) {
        $tables[] = $row[0];
    }
    foreach ($tables as $table) {
        $result = DB::queryRaw('SELECT * FROM ' . $table);
        $num_fields = mysqli_num_fields($result);
        $return .= 'DROP TABLE IF EXISTS ' . $table . ';';
        $row2 = mysqli_fetch_row(DB::queryRaw('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] = str_replace("\n", "\\n", $row[$j]);
                    if (isset($row[$j])) {
                        $return .= '"' . $row[$j] . '"';
                    } else {
                        $return .= '""';
                    }
                    if ($j < $num_fields - 1) {
                        $return .= ',';
                    }
                }
                $return .= ");\n";
            }
        }
        $return .= "\n\n\n";
    }
    DB::useDB($DB_DATABASE);
    // switch back database
    //save file
    $filename = 'db-backup-' . time() . '-' . generate_code(4) . '.sql';
    file_put_contents($filename, $return);
    $order = 1 + DB::queryFirstField('SELECT MAX(order_num) FROM files WHERE category=%i', $category_id);
    $display_name = 'Database Backup: ' . date('Y-m-d');
    DB::insert('files', array('name' => $display_name, 'filename' => $filename, 'permissions' => 'A', 'category' => '0', 'order_num' => $order));
    alert('The file &quot;' . $display_name . '&quot; has been added', 1);
    header('Location: Database');
}