greenplumn IMDColumn 源码
greenplumn IMDColumn 代码
文件路径：/src/backend/gporca/libnaucrates/include/naucrates/md/IMDColumn.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2011 Greenplum, Inc.
//
// @filename:
// IMDColumn.h
//
// @doc:
// Interface class for columns in a metadata cache relation
//---------------------------------------------------------------------------
#ifndef GPMD_IMDColumn_H
#define GPMD_IMDColumn_H
#include "gpos/base.h"
#include "naucrates/dxl/gpdb_types.h"
#include "naucrates/md/IMDId.h"
#include "naucrates/md/IMDInterface.h"
namespace gpmd
{
using namespace gpos;
class CMDName;
//---------------------------------------------------------------------------
// @class:
// IMDColumn
//
// @doc:
// Interface class for columns in a metadata cache relation
//
//---------------------------------------------------------------------------
class IMDColumn : public IMDInterface
{
public:
// column name
virtual CMDName Mdname() const = 0;
// id of attribute type
virtual IMDId *MdidType() const = 0;
virtual INT TypeModifier() const = 0;
// are nulls allowed for this column
virtual BOOL IsNullable() const = 0;
// attribute number in the system catalog
virtual INT AttrNum() const = 0;
// is this a system column
virtual BOOL IsSystemColumn() const = 0;
// is column dropped
virtual BOOL IsDropped() const = 0;
// length of the column
virtual ULONG Length() const = 0;
#ifdef GPOS_DEBUG
// debug print of the column
virtual void DebugPrint(IOstream &os) const = 0;
#endif
};
// IMDColumn array
// typedef CDynamicPtrArray<IMDColumn, CleanupRelease> CMDColumnArray;
} // namespace gpmd
#endif // !GPMD_IMDColumn_H
// EOF
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