ClickHouse/dbms/include/DB/Storages/System/StorageSystemFunctions.h

43 lines
1.1 KiB
C++

#pragma once
#include <ext/shared_ptr_helper.hpp>
#include <DB/Storages/IStorage.h>
#include <DB/Interpreters/Context.h>
namespace DB
{
/** Реализует системную таблицу functions, которая позволяет получить список
* всех обычных и агрегатных функций.
*/
class StorageSystemFunctions : private ext::shared_ptr_helper<StorageSystemFunctions>, public IStorage
{
friend class ext::shared_ptr_helper<StorageSystemFunctions>;
public:
static StoragePtr create(const std::string & name_);
std::string getName() const override { return "SystemFunctions"; }
std::string getTableName() const override { return name; }
const NamesAndTypesList & getColumnsListImpl() const override { return columns; }
BlockInputStreams read(
const Names & column_names,
ASTPtr query,
const Context & context,
const Settings & settings,
QueryProcessingStage::Enum & processed_stage,
size_t max_block_size = DEFAULT_BLOCK_SIZE,
unsigned threads = 1) override;
private:
StorageSystemFunctions(const std::string & name_);
private:
const std::string name;
NamesAndTypesList columns;
};
}