greenplumn CScalarSwitch 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/operators/CScalarSwitch.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2012 EMC Corp.
/
/ @filename:
/ CScalarSwitch.h
/
/ @doc:
/ Scalar switch operator
/---------------------------------------------------------------------------
#ifndef GPOPT_CScalarSwitch_H
#define GPOPT_CScalarSwitch_H
#include "gpos/base.h"
#include "gpopt/base/CDrvdProp.h"
#include "gpopt/operators/CScalar.h"
namespace gpopt
{
using namespace gpos;
/---------------------------------------------------------------------------
/ @class:
/ CScalarSwitch
/
/ @doc:
/ Scalar switch operator. This corresponds to SQL case statments in the form
/ (case expr when expr1 then ret1 when expr2 then ret2 ... else retdef end)
/ The switch operator is represented as follows:
/ Switch
/ |-- expr1
/ |-- SwitchCase
/ | |-- expr1
/ | +-- ret1
/ |-- SwitchCase
/ | |-- expr2
/ | +-- ret2
/ :
/ +-- retdef
/
/---------------------------------------------------------------------------
class CScalarSwitch : public CScalar
{
private:
/ return type
IMDId *m_mdid_type;
/ is operator return type BOOL?
BOOL m_fBoolReturnType;
public:
CScalarSwitch(const CScalarSwitch &) = delete;
/ ctor
CScalarSwitch(CMemoryPool *mp, IMDId *mdid_type);
/ dtor
~CScalarSwitch() override;
/ ident accessors
EOperatorId
Eopid() const override
{
return EopScalarSwitch;
}
/ return a string for operator name
const CHAR *
SzId() const override
{
return "CScalarSwitch";
}
/ the type of the scalar expression
IMDId *
MdidType() const override
{
return m_mdid_type;
}
/ operator specific hash function
ULONG HashValue() const override;
/ match function
BOOL Matches(COperator *pop) const override;
/ sensitivity to order of inputs
BOOL
FInputOrderSensitive() const override
{
return true;
}
/ return a copy of the operator with remapped columns
COperator *
PopCopyWithRemappedColumns(CMemoryPool *, /mp,
UlongToColRefMap *, /colref_mapping,
BOOL /must_exist
) override
{
return PopCopyDefault();
}
/ boolean expression evaluation
EBoolEvalResult
Eber(ULongPtrArray *pdrgpulChildren) const override
{
return EberNullOnAllNullChildren(pdrgpulChildren);
}
/ conversion function
static CScalarSwitch *
PopConvert(COperator *pop)
{
GPOS_ASSERT(nullptr != pop);
GPOS_ASSERT(EopScalarSwitch == pop->Eopid());
return dynamic_cast<CScalarSwitch *>(pop);
}
}; / class CScalarSwitch
} / namespace gpopt
#endif / !GPOPT_CScalarSwitch_H
/ EOF
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