75 lines
2.0 KiB
C++
75 lines
2.0 KiB
C++
/*
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----
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This file is part of SECONDO.
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Copyright (C) 2004, University in Hagen, Department of Computer Science,
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Database Systems for New Applications.
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SECONDO is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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SECONDO is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with SECONDO; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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----
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1.1 Consume2
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The operator "consume2"[2] ~consumes~ a stream of tuples -- presumably
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containing attribute relations -- and builds a nested relation of type
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"nrel2"[2] from it. To distinguish it from "consume"[2] of NestedRelation
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algebra it is postfixed.
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*/
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#ifndef ALGEBRAS_NESTEDRELATION2_CONSUME_H_
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#define ALGEBRAS_NESTEDRELATION2_CONSUME_H_
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#include "Include.h"
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namespace nr2a {
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class Consume
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{
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public:
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struct Info : OperatorInfo
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{
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Info()
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{
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name = "consume2";
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signature = "stream(tuple(X)) -> nrel2(tuple(X))";
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syntax = "_ consume2";
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meaning = "Collects tuples from a stream.";
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example = "query Documents feed unnest2[Authors] consume2";
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supportsProgress = true;
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}
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};
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virtual ~Consume();
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static ListExpr MapType(ListExpr args);
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static ValueMapping functions[];
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static int SelectFunction(ListExpr args);
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static int ConsumeValue(Word* args, Word& result, int message,
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Word& local, Supplier s);
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static CreateCostEstimation costEstimators[];
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protected:
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private:
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Consume(); // Declared, but not defined => Linker error on usage
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};
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} /* namespace nr2a*/
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#endif /* ALGEBRAS_NESTEDRELATION2_CONSUME_H_*/
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