beedb/include/execution/projection_operator.h

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2022-04-04 20:25:01 +02:00
/*------------------------------------------------------------------------------*
* Architecture & Implementation of DBMS *
*------------------------------------------------------------------------------*
* Copyright 2022 Databases and Information Systems Group TU Dortmund *
* Visit us at *
* http://dbis.cs.tu-dortmund.de/cms/en/home/ *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL *
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR *
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, *
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR *
* OTHER DEALINGS IN THE SOFTWARE. *
* *
* Authors: *
* Maximilian Berens <maximilian.berens@tu-dortmund.de> *
* Roland Kühn <roland.kuehn@cs.tu-dortmund.de> *
* Jan Mühlig <jan.muehlig@tu-dortmund.de> *
*------------------------------------------------------------------------------*
*/
#pragma once
#include "unary_operator.h"
#include <cstdint>
#include <string>
#include <table/schema.h>
#include <utility>
#include <vector>
namespace beedb::execution
{
/**
* Applies a new schema to all tuples provided by the children.
* May hide or re-order columns.
*/
class ProjectionOperator final : public UnaryOperator
{
public:
ProjectionOperator(concurrency::Transaction *transaction, table::Schema &&schema);
~ProjectionOperator() override = default;
void open() override;
util::optional<table::Tuple> next() override;
void close() override;
[[nodiscard]] const table::Schema &schema() const override
{
return _schema;
}
private:
const table::Schema _schema;
};
} // namespace beedb::execution