// -----------------------------------------------------------------------------

database_t db_query_14(
	const database_t& database,
	const Actor& actor
);

void db_query_15(
	const database_t& database,
	int year,
	std::ostream& stream = std::cout
);

std::optional<int> db_query_16(
	const database_t& database,
	Type type,
	std::string_view genre
);

size_t db_query_17(
	const database_t& database,
	int rating
);

std::vector<std::string> db_query_18(
	const database_t& database,
	std::string_view genre,
	std::string_view pattern,
	const std::variant<int, std::string>& rating,
	int year
);

void db_query_19(
	const database_t& database,
	int begin,
	int end,
	std::ostream& stream = std::cout
);

template <typename Selector, typename Comparator, typename Serializer>
void db_query_20(
	const database_t& database,
	Selector selector,
	Comparator comparator,
	Serializer serializer,
	std::ostream& stream = std::cout
);

// -----------------------------------------------------------------------------