storages::clickhouse::ExecutionResult Class Reference

Table of Contents

• Public Member Functions
• Detailed Description
• Usage example:
• Member Function Documentation
• As()
• AsContainer()
• AsRows()

#include <userver/storages/clickhouse/execution_result.hpp>

Public Member Functions
	ExecutionResult (impl::BlockWrapperPtr)
	ExecutionResult (ExecutionResult &&) noexcept
size_t	GetColumnsCount () const
	Returns number of columns in underlying block.
size_t	GetRowsCount () const
	Returns number of rows in underlying block columns.
template<typename T >
T	As () &&
template<typename T >
auto	AsRows () &&
template<typename Container >
Container	AsContainer () &&

Detailed Description

Thin wrapper over underlying block of data, returned by storages::clickhouse::Cluster Execute methods

Usage example:

namespace {
 
struct Data final {
  std::vector<uint64_t> numbers;
  std::vector<std::string> strings;
  std::vector<uint64_t> other_numbers;
  std::vector<std::chrono::system_clock::time_point> tps;
};
 
struct RowData final {
  uint64_t number;
  std::string string;
  uint64_t other_number;
  std::chrono::system_clock::time_point tp;
};
 
}  // namespace
 
namespace storages::clickhouse::io {
 
template <>
struct CppToClickhouse<Data> final {
  using mapped_type =
      std::tuple<columns::UInt64Column, columns::StringColumn,
                 columns::UInt64Column, columns::DateTime64ColumnNano>;
};
 
template <>
struct CppToClickhouse<RowData> final {
  using mapped_type =
      std::tuple<columns::UInt64Column, columns::StringColumn,
                 columns::UInt64Column, columns::DateTime64ColumnNano>;
};
 
}  // namespace storages::clickhouse::io

  const Data as_columns{cluster->Execute(common_query).As<Data>()};
  const std::vector<RowData> as_rows{
      cluster->Execute(common_query).AsContainer<std::vector<RowData>>()};
  const auto as_rows_iterable{cluster->Execute(common_query).AsRows<RowData>()};

Definition at line 32 of file execution_result.hpp.

Member Function Documentation

As()

template<typename T >

T storages::clickhouse::ExecutionResult::As

(

)

&&

Converts underlying block to strongly-typed struct of vectors. See clickhouse_io for better understanding of T's requirements.

Definition at line 65 of file execution_result.hpp.

AsContainer()

template<typename Container >

Container storages::clickhouse::ExecutionResult::AsContainer

(

)

&&

Converts underlying block to strongly-typed container. See clickhouse_io for better understanding of Container::value_type's requirements.

Definition at line 89 of file execution_result.hpp.

AsRows()

template<typename T >

auto storages::clickhouse::ExecutionResult::AsRows

(

)

&&

Converts underlying block to iterable of strongly-typed struct. See clickhouse_io for better understanding of T's requirements.

Definition at line 80 of file execution_result.hpp.

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The documentation for this class was generated from the following file:

• userver/storages/clickhouse/execution_result.hpp