ClickHouse/src/Storages/ColumnsDescription.h
2020-10-02 15:38:50 +03:00

153 lines
5.4 KiB
C++

#pragma once
#include <Core/NamesAndTypes.h>
#include <Core/Names.h>
#include <Core/Block.h>
#include <Common/Exception.h>
#include <Storages/ColumnDefault.h>
#include <Storages/ColumnCodec.h>
#include <optional>
#include <Compression/CompressionFactory.h>
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/sequenced_index.hpp>
#include <boost/multi_index/ordered_index.hpp>
#include <boost/multi_index/member.hpp>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
}
/// Description of a single table column (in CREATE TABLE for example).
struct ColumnDescription
{
String name;
DataTypePtr type;
ColumnDefault default_desc;
String comment;
ASTPtr codec;
ASTPtr ttl;
ColumnDescription() = default;
ColumnDescription(ColumnDescription &&) = default;
ColumnDescription(const ColumnDescription &) = default;
ColumnDescription(String name_, DataTypePtr type_);
bool operator==(const ColumnDescription & other) const;
bool operator!=(const ColumnDescription & other) const { return !(*this == other); }
void writeText(WriteBuffer & buf) const;
void readText(ReadBuffer & buf);
};
/// Description of multiple table columns (in CREATE TABLE for example).
class ColumnsDescription
{
public:
ColumnsDescription() = default;
explicit ColumnsDescription(NamesAndTypesList ordinary_);
/// `after_column` can be a Nested column name;
void add(ColumnDescription column, const String & after_column = String(), bool first = false);
/// `column_name` can be a Nested column name;
void remove(const String & column_name);
/// Rename column. column_from and column_to cannot be nested columns.
/// TODO add ability to rename nested columns
void rename(const String & column_from, const String & column_to);
/// NOTE Must correspond with Nested::flatten function.
void flattenNested(); /// TODO: remove, insert already flattened Nested columns.
bool operator==(const ColumnsDescription & other) const { return columns == other.columns; }
bool operator!=(const ColumnsDescription & other) const { return !(*this == other); }
auto begin() const { return columns.begin(); }
auto end() const { return columns.end(); }
NamesAndTypesList getOrdinary() const;
NamesAndTypesList getMaterialized() const;
NamesAndTypesList getAliases() const;
NamesAndTypesList getAllPhysical() const; /// ordinary + materialized.
NamesAndTypesList getAll() const; /// ordinary + materialized + aliases
using ColumnTTLs = std::unordered_map<String, ASTPtr>;
ColumnTTLs getColumnTTLs() const;
bool has(const String & column_name) const;
bool hasNested(const String & column_name) const;
const ColumnDescription & get(const String & column_name) const;
template <typename F>
void modify(const String & column_name, F && f)
{
modify(column_name, String(), false, std::forward<F>(f));
}
template <typename F>
void modify(const String & column_name, const String & after_column, bool first, F && f)
{
auto it = columns.get<1>().find(column_name);
if (it == columns.get<1>().end())
throw Exception("Cannot find column " + column_name + " in ColumnsDescription", ErrorCodes::LOGICAL_ERROR);
if (!columns.get<1>().modify(it, std::forward<F>(f)))
throw Exception("Cannot modify ColumnDescription for column " + column_name + ": column name cannot be changed", ErrorCodes::LOGICAL_ERROR);
modifyColumnOrder(column_name, after_column, first);
}
Names getNamesOfPhysical() const;
bool hasPhysical(const String & column_name) const;
NameAndTypePair getPhysical(const String & column_name) const;
ColumnDefaults getDefaults() const; /// TODO: remove
bool hasDefault(const String & column_name) const;
bool hasDefaults() const;
std::optional<ColumnDefault> getDefault(const String & column_name) const;
/// Does column has non default specified compression codec
bool hasCompressionCodec(const String & column_name) const;
CompressionCodecPtr getCodecOrDefault(const String & column_name, CompressionCodecPtr default_codec) const;
CompressionCodecPtr getCodecOrDefault(const String & column_name) const;
ASTPtr getCodecDescOrDefault(const String & column_name, CompressionCodecPtr default_codec) const;
String toString() const;
static ColumnsDescription parse(const String & str);
size_t size() const
{
return columns.size();
}
bool empty() const
{
return columns.empty();
}
/// Keep the sequence of columns and allow to lookup by name.
using Container = boost::multi_index_container<
ColumnDescription,
boost::multi_index::indexed_by<
boost::multi_index::sequenced<>,
boost::multi_index::ordered_unique<boost::multi_index::member<ColumnDescription, String, &ColumnDescription::name>>>>;
private:
Container columns;
void modifyColumnOrder(const String & column_name, const String & after_column, bool first);
};
/// Validate default expressions and corresponding types compatibility, i.e.
/// default expression result can be casted to column_type. Also checks, that we
/// don't have strange constructions in default expression like SELECT query or
/// arrayJoin function.
Block validateColumnsDefaultsAndGetSampleBlock(ASTPtr default_expr_list, const NamesAndTypesList & all_columns, const Context & context);
}