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57 lines
1.3 KiB
C++
57 lines
1.3 KiB
C++
#pragma once
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#include <Poco/SharedPtr.h>
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#include <DB/DataStreams/IProfilingBlockInputStream.h>
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#include <DB/Columns/ColumnConst.h>
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#include <DB/Core/ColumnWithNameAndType.h>
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namespace DB
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{
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/** Добавляет в блок материализованный const column с заданным значением.
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*/
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template <typename ColumnType>
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class AddingConstColumnBlockInputStream : public IProfilingBlockInputStream
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{
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public:
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AddingConstColumnBlockInputStream(
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BlockInputStreamPtr input_,
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DataTypePtr data_type_,
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ColumnType value_,
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String column_name_)
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: data_type(data_type_), value(value_), column_name(column_name_)
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{
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children.push_back(input_);
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}
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String getName() const { return "AddingConstColumnBlockInputStream"; }
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String getID() const
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{
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std::stringstream res;
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res << "AddingConstColumn(" << children.back()->getID() << ")";
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return res.str();
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}
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protected:
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Block readImpl()
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{
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Block res = children.back()->read();
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if (!res)
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return res;
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ColumnPtr column_ptr = (new ColumnConst<ColumnType> (res.rows(), value, data_type))->convertToFullColumn();
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ColumnWithNameAndType column(column_ptr, data_type, column_name);
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res.insert(column);
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return res;
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}
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private:
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DataTypePtr data_type;
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ColumnType value;
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String column_name;
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};
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}
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