ClickHouse/dbms/include/DB/Storages/StorageView.h

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#pragma once
#include <ext/shared_ptr_helper.hpp>
#include <DB/Parsers/ASTSelectQuery.h>
#include <DB/Storages/IStorage.h>
namespace DB
{
class StorageView : private ext::shared_ptr_helper<StorageView>, public IStorage
{
friend class ext::shared_ptr_helper<StorageView>;
public:
static StoragePtr create(
const String & table_name_,
const String & database_name_,
Context & context_,
ASTPtr & query_,
NamesAndTypesListPtr columns_,
const NamesAndTypesList & materialized_columns_,
const NamesAndTypesList & alias_columns_,
const ColumnDefaults & column_defaults_);
std::string getName() const override { return "View"; }
std::string getTableName() const override { return table_name; }
const NamesAndTypesList & getColumnsListImpl() const override { return *columns; }
ASTPtr getInnerQuery() const { return inner_query.clone(); };
/// Пробрасывается внутрь запроса и решается на его уровне.
bool supportsSampling() const override { return true; }
bool supportsFinal() const override { return true; }
bool supportsParallelReplicas() const override { return true; }
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;
void drop() override;
protected:
String select_database_name;
String select_table_name;
String table_name;
String database_name;
ASTSelectQuery inner_query;
Context & context;
NamesAndTypesListPtr columns;
StorageView(
const String & table_name_,
const String & database_name_,
Context & context_,
ASTPtr & query_,
NamesAndTypesListPtr columns_,
const NamesAndTypesList & materialized_columns_,
const NamesAndTypesList & alias_columns_,
const ColumnDefaults & column_defaults_);
private:
/// Достать из самого внутреннего подзапроса имя базы данных и таблицы: select_database_name, select_table_name.
void extractDependentTable(const ASTSelectQuery & query);
};
}