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#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;
};
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