greenplumn CScalar 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/operators/CScalar.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2009 Greenplum, Inc.
/
/ @filename:
/ CScalar.h
/
/ @doc:
/ Base class for all scalar operators
/---------------------------------------------------------------------------
#ifndef GPOPT_CScalar_H
#define GPOPT_CScalar_H
#include "gpos/base.h"
#include "gpopt/base/CDrvdProp.h"
#include "gpopt/base/CPartInfo.h"
#include "gpopt/mdcache/CMDAccessor.h"
#include "gpopt/operators/COperator.h"
#include "naucrates/md/IMDId.h"
namespace gpopt
{
using namespace gpos;
using namespace gpmd;
/ forward declaration
class CColRefSet;
/---------------------------------------------------------------------------
/ @class:
/ CScalar
/
/ @doc:
/ base class for all scalar operators
/
/---------------------------------------------------------------------------
class CScalar : public COperator
{
public:
/ possible results of Boolean evaluation of a scalar expression
enum EBoolEvalResult
{
EberTrue = 1, / TRUE
EberFalse, / FALSE
EberNull, / NULL
EberNotTrue, / FALSE or NULL
EberAny, / Any result is possible
EerSentinel
};
private:
/ helper for combining partition consumer arrays of scalar children
static CPartInfo *PpartinfoDeriveCombineScalar(CMemoryPool *mp,
CExpressionHandle &exprhdl);
protected:
/ perform conjunction of child boolean evaluation results
static EBoolEvalResult EberConjunction(ULongPtrArray *pdrgpulChildren);
/ perform disjunction of child boolean evaluation results
static EBoolEvalResult EberDisjunction(ULongPtrArray *pdrgpulChildren);
/ return Null if any child is Null
static EBoolEvalResult EberNullOnAnyNullChild(
ULongPtrArray *pdrgpulChildren);
/ return Null if all children are Null
static EBoolEvalResult EberNullOnAllNullChildren(
ULongPtrArray *pdrgpulChildren);
public:
CScalar(const CScalar &) = delete;
/ ctor
explicit CScalar(CMemoryPool *mp) : COperator(mp)
{
}
/ dtor
~CScalar() override = default;
/ type of operator
BOOL
FScalar() const override
{
GPOS_ASSERT(!FPhysical() && !FLogical() && !FPattern());
return true;
}
/ create derived properties container
CDrvdProp *PdpCreate(CMemoryPool *mp) const override;
/ create required properties container
CReqdProp *PrpCreate(CMemoryPool *mp) const override;
/ return locally defined columns
virtual CColRefSet *
PcrsDefined(CMemoryPool *mp,
CExpressionHandle & / exprhdl
)
{
/ return an empty set of column refs
return GPOS_NEW(mp) CColRefSet(mp);
}
/ return columns containing set-returning function
virtual CColRefSet *
PcrsSetReturningFunction(CMemoryPool *mp,
CExpressionHandle & / exprhdl
)
{
/ return an empty set of column refs
return GPOS_NEW(mp) CColRefSet(mp);
}
/ return locally used columns
virtual CColRefSet *
PcrsUsed(CMemoryPool *mp,
CExpressionHandle & / exprhdl
)
{
/ return an empty set of column refs
return GPOS_NEW(mp) CColRefSet(mp);
}
/ derive partition consumer info
virtual CPartInfo *
PpartinfoDerive(CMemoryPool *mp, CExpressionHandle &exprhdl) const
{
return PpartinfoDeriveCombineScalar(mp, exprhdl);
}
/ derive function properties
virtual CFunctionProp *
DeriveFunctionProperties(CMemoryPool *mp, CExpressionHandle &exprhdl) const
{
return PfpDeriveFromChildren(mp, exprhdl,
IMDFunction::EfsImmutable, / efdaDefault
false, / fHasVolatileFunctionScan
false / fScan
);
}
/ derive subquery existence
virtual BOOL FHasSubquery(CExpressionHandle &exprhdl);
/ derive non-scalar function existence
virtual BOOL FHasNonScalarFunction(CExpressionHandle &exprhdl);
virtual BOOL FHasScalarArrayCmp(CExpressionHandle &exprhdl);
/ boolean expression evaluation
virtual EBoolEvalResult
Eber(ULongPtrArray * / pdrgpulChildren
) const
{
/ by default, evaluation result can be false, true or NULL
return EberAny;
}
/ perform boolean evaluation of the given expression tree
static EBoolEvalResult EberEvaluate(CMemoryPool *mp,
CExpression *pexprScalar);
/ conversion function
static CScalar *
PopConvert(COperator *pop)
{
GPOS_ASSERT(nullptr != pop);
GPOS_ASSERT(pop->FScalar());
return dynamic_cast<CScalar *>(pop);
}
/ the type of the scalar expression
virtual IMDId *MdidType() const = 0;
/ the type modifier of the scalar expression
virtual INT
TypeModifier() const
{
return default_type_modifier;
}
}; / class CScalar
} / namespace gpopt
#endif / !GPOPT_CScalar_H
/ EOF
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