#pragma once #include <database/engine.hpp> #include <database/statement.hpp> #include <database/query.hpp> #include <logger/logger.hpp> #include <database/row.hpp> #include <utils/optional_bool.hpp> #include <vector> #include <string> using namespace std::string_literals; template <typename T> typename std::enable_if<std::is_integral<T>::value, std::int64_t>::type extract_row_value(Statement& statement, const int i) { return statement.get_column_int64(i); } template <typename T> typename std::enable_if<std::is_same<std::string, T>::value, T>::type extract_row_value(Statement& statement, const int i) { return statement.get_column_text(i); } template <typename T> typename std::enable_if<std::is_same<OptionalBool, T>::value, T>::type extract_row_value(Statement& statement, const int i) { const auto integer = statement.get_column_int(i); OptionalBool result; if (integer > 0) result.set_value(true); else if (integer < 0) result.set_value(false); return result; } template <std::size_t N=0, typename... T> typename std::enable_if<N < sizeof...(T), void>::type extract_row_values(Row<T...>& row, Statement& statement) { using ColumnType = typename std::remove_reference<decltype(std::get<N>(row.columns))>::type; auto&& column = std::get<N>(row.columns); column.value = static_cast<decltype(column.value)>(extract_row_value<typename ColumnType::real_type>(statement, N)); extract_row_values<N+1>(row, statement); } template <std::size_t N=0, typename... T> typename std::enable_if<N == sizeof...(T), void>::type extract_row_values(Row<T...>&, Statement&) {} template <typename... T> struct SelectQuery: public Query { SelectQuery(std::string table_name): Query("SELECT"), table_name(table_name) { this->insert_col_name(); this->body += " from " + this->table_name; } template <std::size_t N=0> typename std::enable_if<N < sizeof...(T), void>::type insert_col_name() { using ColumnsType = std::tuple<T...>; using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<ColumnsType>()))>::type; this->body += " " + std::string{ColumnType::name}; if (N < (sizeof...(T) - 1)) this->body += ", "; this->insert_col_name<N+1>(); } template <std::size_t N=0> typename std::enable_if<N == sizeof...(T), void>::type insert_col_name() {} SelectQuery& where() { this->body += " WHERE "; return *this; }; SelectQuery& order_by() { this->body += " ORDER BY "; return *this; } SelectQuery& limit() { this->body += " LIMIT "; return *this; } auto execute(DatabaseEngine& db) { std::vector<Row<T...>> rows; auto statement = db.prepare(this->body); statement->bind(std::move(this->params)); while (statement->step() == StepResult::Row) { log_debug("one result."); Row<T...> row(this->table_name); extract_row_values(row, *statement); rows.push_back(row); } return rows; } const std::string table_name; };