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68 lines
2.1 KiB
C++
68 lines
2.1 KiB
C++
#pragma once
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#include <Poco/SharedPtr.h>
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#include <DB/DataStreams/IBlockOutputStream.h>
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#include <DB/Columns/ColumnConst.h>
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#include <DB/Storages/ColumnDefault.h>
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#include <DB/Interpreters/Context.h>
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#include <DB/Interpreters/evaluateMissingDefaults.h>
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namespace DB
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{
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/** Добавляет в блок недостающие столбцы со значениями по-умолчанию.
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* Эти столбцы - материалированные (не константы).
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*/
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class AddingDefaultBlockOutputStream : public IBlockOutputStream
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{
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public:
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AddingDefaultBlockOutputStream(
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BlockOutputStreamPtr output_,
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NamesAndTypesListPtr required_columns_,
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const ColumnDefaults & column_defaults_,
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const Context & context_,
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bool only_explicit_column_defaults_)
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: output(output_), required_columns(required_columns_),
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column_defaults(column_defaults_), context(context_),
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only_explicit_column_defaults(only_explicit_column_defaults_)
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{
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}
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void write(const Block & block) override
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{
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Block res = block;
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/// Вычисляет явно указанные (в column_defaults) значения по-умолчанию.
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/** @todo if somehow block does not contain values for implicitly-defaulted columns that are prerequisites
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* for explicitly-defaulted ones, exception will be thrown during evaluating such columns
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* (implicitly-defaulted columns are evaluated on the line after following one. */
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evaluateMissingDefaults(res, *required_columns, column_defaults, context);
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/// Добавляет не указанные значения по-умолчанию.
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if (!only_explicit_column_defaults)
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/// @todo this line may be moved before `evaluateMissingDefaults` with passing {required_columns - explicitly-defaulted columns}
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res.addDefaults(*required_columns);
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output->write(res);
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}
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void flush() override { output->flush(); }
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void writePrefix() override { output->writePrefix(); }
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void writeSuffix() override { output->writeSuffix(); }
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private:
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BlockOutputStreamPtr output;
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NamesAndTypesListPtr required_columns;
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const ColumnDefaults & column_defaults;
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Context context;
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bool only_explicit_column_defaults;
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};
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}
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