greenplumn IDatumOid 源码
greenplumn IDatumOid 代码
文件路径：/src/backend/gporca/libnaucrates/include/naucrates/base/IDatumOid.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2012 EMC Corp.
//
// @filename:
// IDatumOid.h
//
// @doc:
// Base abstract class for oid representation
//---------------------------------------------------------------------------
#ifndef GPNAUCRATES_IDatumOid_H
#define GPNAUCRATES_IDatumOid_H
#include "gpos/base.h"
#include "naucrates/base/IDatum.h"
namespace gpnaucrates
{
//---------------------------------------------------------------------------
// @class:
// IDatumOid
//
// @doc:
// Base abstract class for oid representation
//
//---------------------------------------------------------------------------
class IDatumOid : public IDatum
{
private:
public:
IDatumOid(const IDatumOid &) = delete;
// ctor
IDatumOid() = default;
// dtor
~IDatumOid() override = default;
// accessor for datum type
IMDType::ETypeInfo
GetDatumType() override
{
return IMDType::EtiOid;
}
// accessor of oid value
virtual OID OidValue() const = 0;
// can datum be mapped to a double
BOOL
IsDatumMappableToDouble() const override
{
return true;
}
// map to double for stats computation
CDouble
GetDoubleMapping() const override
{
return CDouble(GetLINTMapping());
}
// can datum be mapped to LINT
BOOL
IsDatumMappableToLINT() const override
{
return true;
}
// map to LINT for statistics computation
LINT
GetLINTMapping() const override
{
return LINT(OidValue());
}
// byte array representation of datum
const BYTE *
GetByteArrayValue() const override
{
GPOS_ASSERT(!"Invalid invocation of MakeCopyOfValue");
return nullptr;
}
// does the datum need to be padded before statistical derivation
BOOL
NeedsPadding() const override
{
return false;
}
// return the padded datum
IDatum *
MakePaddedDatum(CMemoryPool *, // mp,
ULONG // col_len
) const override
{
GPOS_ASSERT(!"Invalid invocation of MakePaddedDatum");
return nullptr;
}
// does datum support like predicate
BOOL
SupportsLikePredicate() const override
{
return false;
}
// return the default scale factor of like predicate
CDouble
GetLikePredicateScaleFactor() const override
{
GPOS_ASSERT(!"Invalid invocation of DLikeSelectivity");
return false;
}
}; // class IDatumOid
} // namespace gpnaucrates
#endif // !GPNAUCRATES_IDatumOid_H
// EOF
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