private function addSqlite3Node()
    {
        $builder = new TreeBuilder('sqlite3');
        $node    = $this->getRootNode($builder, 'sqlite3');

        $node
            ->addDefaultsIfNotSet()
            ->children()
                ->scalarNode('connection_id')->defaultNull()->end()
                ->scalarNode('file_name')->defaultNull()->end()
                ->scalarNode('table_name')->defaultNull()->end()
            ->end()
        ;

        return $node;
    }