Many-to-Many.Classic Junction Table

        protected function doGetCustomTemplate($type, $part, $mode, &$result, &$params)
        {
            if ($mode == PageMode::FormEdit || $mode == PageMode::FormInsert) {
                $result = 'many_to_many_junction_custom_form.tpl';
                        
                // Get genre list
                $params['Genres'] = $this->GetConnection()->fetchAll("SELECT * FROM genres");
                                
                // Extract edited movie ID from GET parameters  
                if (GetApplication()->IsGETValueSet('pk0')) {
                    $movieId = GetApplication()->GetGETValue('pk0');
                }
            
                $movieGenres = array();
                if (isset($movieId)) {
                    // Get movie genres from junction table
                    $sql = "SELECT genre_id FROM movie_genres WHERE movie_id = $movieId";
                    $queryResult = $this->GetConnection()->fetchAll($sql);
                    foreach ($queryResult as $item) {
                        $movieGenres[] = $item['genre_id'];
                    }
                }
                $params['MovieGenres'] = $movieGenres;
            }
        }

        protected function doAfterInsertRecord($page, $rowData, $tableName, &$success, &$message, &$messageDisplayTime)
        {
            if ($success && GetApplication()->IsPOSTValueSet('genres_edit')) {
                $genres = GetApplication()->GetPOSTValue('genres_edit');
                $lastInsertId = $this->GetConnection()->GetLastInsertId();
                foreach ($genres as $genre) {
                    $sql = sprintf('INSERT INTO movie_genres VALUES(%d, %d);', $lastInsertId, $genre);
                    $this->GetConnection()->ExecSQL($sql);
                }
            }
        }

        protected function doAfterUpdateRecord($page, $rowData, $tableName, &$success, &$message, &$messageDisplayTime)
        {
            if ($success && GetApplication()->IsPOSTValueSet('genres_edit')) {
                $sql = sprintf('DELETE FROM movie_genres WHERE movie_id = %d;', $rowData['id']);
                $this->GetConnection()->ExecSQL($sql);
                $genres = GetApplication()->GetPOSTValue('genres_edit');
                foreach ($genres as $genre) {
                    $sql = sprintf('INSERT INTO movie_genres VALUES(%d, %d);', $rowData['id'], $genre);
                    $this->GetConnection()->ExecSQL($sql);
                }
            }
        }