greenplumn CLogicalLeftOuterJoin 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/operators/CLogicalLeftOuterJoin.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2011 EMC Corp.
/
/ @filename:
/ CLogicalLeftOuterJoin.h
/
/ @doc:
/ Left outer join operator
/---------------------------------------------------------------------------
#ifndef GPOS_CLogicalLeftOuterJoin_H
#define GPOS_CLogicalLeftOuterJoin_H
#include "gpos/base.h"
#include "gpopt/operators/CLogicalJoin.h"
namespace gpopt
{
/---------------------------------------------------------------------------
/ @class:
/ CLogicalLeftOuterJoin
/
/ @doc:
/ Left outer join operator
/
/---------------------------------------------------------------------------
class CLogicalLeftOuterJoin : public CLogicalJoin
{
private:
public:
CLogicalLeftOuterJoin(const CLogicalLeftOuterJoin &) = delete;
/ ctor
explicit CLogicalLeftOuterJoin(
CMemoryPool *mp, CXform::EXformId origin_xform = CXform::ExfSentinel);
/ dtor
~CLogicalLeftOuterJoin() override = default;
/ ident accessors
EOperatorId
Eopid() const override
{
return EopLogicalLeftOuterJoin;
}
/ return a string for operator name
const CHAR *
SzId() const override
{
return "CLogicalLeftOuterJoin";
}
/ return true if we can pull projections up past this operator from its given child
BOOL
FCanPullProjectionsUp(ULONG child_index) const override
{
return (0 == child_index);
}
/-------------------------------------------------------------------------------------
/ Derived Relational Properties
/-------------------------------------------------------------------------------------
/ derive not nullable output columns
CColRefSet *
DeriveNotNullColumns(CMemoryPool *, / mp
CExpressionHandle &exprhdl) const override
{
/ left outer join passes through not null columns from outer child only
return PcrsDeriveNotNullPassThruOuter(exprhdl);
}
/ derive max card
CMaxCard DeriveMaxCard(CMemoryPool *mp,
CExpressionHandle &exprhdl) const override;
/ derive constraint property
CPropConstraint *
DerivePropertyConstraint(CMemoryPool *, /mp,
CExpressionHandle &exprhdl) const override
{
return PpcDeriveConstraintPassThru(exprhdl, 0 /*ulChild*/);
}
/-------------------------------------------------------------------------------------
/ Transformations
/-------------------------------------------------------------------------------------
/ candidate set of xforms
CXformSet *PxfsCandidates(CMemoryPool *mp) const override;
/-------------------------------------------------------------------------------------
/-------------------------------------------------------------------------------------
/-------------------------------------------------------------------------------------
/ conversion function
static CLogicalLeftOuterJoin *
PopConvert(COperator *pop)
{
GPOS_ASSERT(nullptr != pop);
GPOS_ASSERT(EopLogicalLeftOuterJoin == pop->Eopid());
return dynamic_cast<CLogicalLeftOuterJoin *>(pop);
}
}; / class CLogicalLeftOuterJoin
} / namespace gpopt
#endif / !GPOS_CLogicalLeftOuterJoin_H
/ EOF
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