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secondo/Algebras/NestedRelation2/GenRel.h
2026-01-23 17:03:45 +08:00

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/*
----
This file is part of SECONDO.
Copyright (C) 2004, University in Hagen, Department of Computer Science,
Database Systems for New Applications.
SECONDO is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
SECONDO is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with SECONDO; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
----
The operator "genRel"[2] is used to generate nested relations of several forms
for testing. It features the possibility to build relations of types
"nrel2"[2] and "arel2"[2], "nrel"[2] and "arel"[2] as well as "record"[2] and
"vector"[2]. It is possible to nest them to arbitrary depth.
Relations can contain a specifiable amount of attributes of different atomic
types and can grow to an arbitrary length given. For attributes of types
"string"[2] and "text"[2] the length is definable. Furthermore the selectivity
can be adjusted to support the testing of filter conditions.
*/
#ifndef ALGEBRAS_NESTEDRELATION2_OPERATORS_GENREL_H_
#define ALGEBRAS_NESTEDRELATION2_OPERATORS_GENREL_H_
#include "Stream.h"
namespace nr2a {
class GenRel
{
public:
struct Info : OperatorInfo
{
Info()
{
name = "genRel";
signature = "\"nrel\" x string x int x int x string x int x int x "
"RELTYPE -> nrel(tuple(X))";
appendSignature(
"\"arel\" x string x int x int x string x int x int x "
"RELTYPE -> arel(tuple(X))");
appendSignature(
"\"nrel2\" x string x int x int x string x int x int x "
"RELTYPE -> nrel2(tuple(X))");
appendSignature(
"\"arel2\" x string x int x int x string x int x int x "
"RELTYPE -> arel2(tuple(X))");
appendSignature(
"\"vector\" x string x int x int x string x int x int x "
"RELTYPE -> vector(record(X))");
syntax = "genRel(_, _, _, _, _, _, _)";
meaning =
"Produces a nested relation for testing. The parameters "
"are (left to right):\n"
"Resulting type, names prefix, number of attributes, "
"number of tuples, attributes type, string length, "
"selectivity, data of subrelation where "
"RELTYPE is one of arel(tuple(X)), arel2(tuple(X)), "
"vector(record(X))\n"
"attributes type may be: bool, int, real, string or text";
example = "query genRel(\"nrel2\", \"Attr\", 10, 100, \"int\", "
"0, 0, undefined) consume";
}
};
virtual ~GenRel();
static ListExpr MapType(ListExpr args);
static ValueMapping functions[];
static int SelectFunction(ListExpr args);
static int GenRelValue(Word* args, Word& result, int message,
Word& local, Supplier s);
static CreateCostEstimation costEstimators[];
protected:
private:
GenRel(); // Declared, but not defined => Linker error on usage
};
} /* namespace nr2a*/
#endif /* ALGEBRAS_NESTEDRELATION2_OPERATORS_GENREL_H_*/