ClickHouse/dbms/include/DB/Interpreters/InterpreterCreateQuery.h

#pragma once

#include <DB/Storages/IStorage.h>
#include <DB/Interpreters/Context.h>
#include <DB/Interpreters/IInterpreter.h>
#include <DB/Storages/ColumnDefault.h>
#include <DB/Common/ThreadPool.h>


namespace DB
{

class ASTCreateQuery;


/** Allows to create new table or database,
  *  or create an object for existing table or database.
  */
class InterpreterCreateQuery : public IInterpreter
{
public:
	InterpreterCreateQuery(ASTPtr query_ptr_, Context & context_);

	BlockIO execute() override;

	/// List of columns and their types in AST.
	static ASTPtr formatColumns(const NamesAndTypesList & columns);
	static ASTPtr formatColumns(
		NamesAndTypesList columns,
		const NamesAndTypesList & materialized_columns,
		const NamesAndTypesList & alias_columns,
		const ColumnDefaults & column_defaults);

	void setDatabaseLoadingThreadpool(ThreadPool & thread_pool_)
	{
		thread_pool = &thread_pool_;
	}

	void setForceRestoreData(bool has_force_restore_data_flag_)
	{
		has_force_restore_data_flag = has_force_restore_data_flag_;
	}

	struct ColumnsInfo
	{
		NamesAndTypesListPtr columns = std::make_shared<NamesAndTypesList>();
		NamesAndTypesList materialized_columns;
		NamesAndTypesList alias_columns;
		ColumnDefaults column_defaults;
	};

	/// Obtain information about columns, their types and default values, for case when columns in CREATE query is specified explicitly.
	static ColumnsInfo getColumnsInfo(const ASTPtr & columns, const Context & context);

private:
	void createDatabase(ASTCreateQuery & create);
	BlockIO createTable(ASTCreateQuery & create);

	/// Calculate list of columns of table and return it.
	ColumnsInfo setColumns(ASTCreateQuery & create, const Block & as_select_sample, const StoragePtr & as_storage) const;
	String setEngine(ASTCreateQuery & create, const StoragePtr & as_storage) const;

	ASTPtr query_ptr;
	Context context;

	/// Using while loading database.
	ThreadPool * thread_pool = nullptr;

	/// Skip safety threshold when loading tables.
	bool has_force_restore_data_flag = false;
};


}