greenplumn CDXLScalarSubquery 源码
greenplumn CDXLScalarSubquery 代码
文件路径：/src/backend/gporca/libnaucrates/include/naucrates/dxl/operators/CDXLScalarSubquery.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2011 EMC, Corp.
//
// @filename:
// CDXLScalarSubquery.h
//
// @doc:
// Class for representing subqueries computing scalar values
//---------------------------------------------------------------------------
#ifndef GPDXL_CDXLScalarSubquery_H
#define GPDXL_CDXLScalarSubquery_H
#include "gpos/base.h"
#include "naucrates/dxl/operators/CDXLNode.h"
#include "naucrates/dxl/operators/CDXLScalar.h"
namespace gpdxl
{
//---------------------------------------------------------------------------
// @class:
// CDXLScalarSubquery
//
// @doc:
// Class for representing subqueries computing scalar values
//
//---------------------------------------------------------------------------
class CDXLScalarSubquery : public CDXLScalar
{
private:
// id of column computed by the subquery
ULONG m_colid;
public:
CDXLScalarSubquery(CDXLScalarSubquery &) = delete;
// ctor/dtor
CDXLScalarSubquery(CMemoryPool *mp, ULONG colid);
~CDXLScalarSubquery() override;
// ident accessors
Edxlopid GetDXLOperator() const override;
// colid of subquery column
ULONG
GetColId() const
{
return m_colid;
}
// name of the operator
const CWStringConst *GetOpNameStr() const override;
// serialize operator in DXL format
void SerializeToDXL(CXMLSerializer *, const CDXLNode *) const override;
// conversion function
static CDXLScalarSubquery *
Cast(CDXLOperator *dxl_op)
{
GPOS_ASSERT(nullptr != dxl_op);
GPOS_ASSERT(EdxlopScalarSubquery == dxl_op->GetDXLOperator());
return dynamic_cast<CDXLScalarSubquery *>(dxl_op);
}
// does the operator return a boolean result
BOOL
HasBoolResult(CMDAccessor * //md_accessor
) const override
{
return true;
}
#ifdef GPOS_DEBUG
// checks whether the operator has valid structure, i.e. number and
// types of child nodes
void AssertValid(const CDXLNode *dxlnode,
BOOL validate_children) const override;
#endif // GPOS_DEBUG
};
} // namespace gpdxl
#endif // !GPDXL_CDXLScalarSubquery_H
// EOF
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