greenplumn CMDColumn 源码
greenplumn CMDColumn 代码
文件路径：/src/backend/gporca/libnaucrates/include/naucrates/md/CMDColumn.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2011 Greenplum, Inc.
//
// @filename:
// CMDColumn.h
//
// @doc:
// Class for representing metadata about relation's columns.
//---------------------------------------------------------------------------
#ifndef GPMD_CDXLColumn_H
#define GPMD_CDXLColumn_H
#include "gpos/base.h"
#include "naucrates/md/CMDName.h"
#include "naucrates/md/IMDColumn.h"
// fwd decl
namespace gpdxl
{
class CDXLNode;
class CXMLSerializer;
} // namespace gpdxl
namespace gpmd
{
//---------------------------------------------------------------------------
// @class:
// CMDColumn
//
// @doc:
// Class for representing metadata about relation's columns.
//
//---------------------------------------------------------------------------
class CMDColumn : public IMDColumn
{
private:
// attribute name
CMDName *m_mdname;
// attribute number
INT m_attno;
// column type
IMDId *m_mdid_type;
INT m_type_modifier;
// is NULL an allowed value for the attribute
BOOL m_is_nullable;
// is column dropped
BOOL m_is_dropped;
// length of the column
ULONG m_length;
// default value expression
gpdxl::CDXLNode *m_dxl_default_val;
public:
CMDColumn(const CMDColumn &) = delete;
// ctor
CMDColumn(CMDName *mdname, INT attrnum, IMDId *mdid_type, INT type_modifier,
BOOL is_nullable, BOOL is_dropped,
gpdxl::CDXLNode *dxl_dafault_value,
ULONG length = gpos::ulong_max);
// dtor
~CMDColumn() override;
// accessors
CMDName Mdname() const override;
// column type
IMDId *MdidType() const override;
INT TypeModifier() const override;
// attribute number
INT AttrNum() const override;
// is this a system column
BOOL
IsSystemColumn() const override
{
return (0 > m_attno);
}
// length of the column
ULONG
Length() const override
{
return m_length;
}
// is the column nullable
BOOL IsNullable() const override;
// is the column dropped
BOOL IsDropped() const override;
// serialize metadata object in DXL format given a serializer object
virtual void Serialize(gpdxl::CXMLSerializer *) const;
#ifdef GPOS_DEBUG
// debug print of the column
void DebugPrint(IOstream &os) const override;
#endif
};
// array of metadata column descriptor
using CMDColumnArray = CDynamicPtrArray<CMDColumn, CleanupRelease>;
} // namespace gpmd
#endif // !GPMD_CDXLColumn_H
// EOF
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