Magazyn Internet 2000 May/MICD_2000_05.iso/CBuilder5/INSTALL/DATA1.CAB/Program_Built_Files/Include/Atl/atldbcli.h

C/C++ Source or Header | 2000-02-01 | 103.3 KB | 3,838 lines

// This is a part of the Active Template Library.
// Copyright (C) 1996-1998 Microsoft Corporation
// All rights reserved.
//
// This source code is only intended as a supplement to the
// Active Template Library Reference and related
// electronic documentation provided with the library.
// See these sources for detailed information regarding the
// Active Template Library product.

// ATLDBCLI.H : ATL consumer code for OLEDB

#ifndef __ATLDBCLI_H_
#define __ATLDBCLI_H_

#ifdef __BORLANDC__
#ifdef _BCB_ATL_DEBUG
#define _DEBUG
#endif
#endif

#ifndef __cplusplus
    #error ATL requires C++ compilation (use a .cpp suffix)
#endif

#ifndef _ATLBASE_H
#include "atlbase.h"
#endif

#ifndef __oledb_h__
#include <oledb.h>
#endif // __oledb_h__

#include <msdaguid.h>
#include <msdasc.h>

namespace ATL
{

#define DEFINE_OLEDB_TYPE_FUNCTION(ctype, oledbtype) \
    inline DBTYPE _GetOleDBType(ctype&) \
    { \
        return oledbtype; \
    }
    inline DBTYPE _GetOleDBType(BYTE[])
    {
        return DBTYPE_BYTES;
    }
    inline DBTYPE _GetOleDBType(CHAR[])
    {
        return DBTYPE_STR;
    }
    inline DBTYPE _GetOleDBType(WCHAR[])
    {
        return DBTYPE_WSTR;
    }

    DEFINE_OLEDB_TYPE_FUNCTION(signed char      ,DBTYPE_I1)
    DEFINE_OLEDB_TYPE_FUNCTION(SHORT            ,DBTYPE_I2)     // DBTYPE_BOOL
    DEFINE_OLEDB_TYPE_FUNCTION(int              ,DBTYPE_I4)
    DEFINE_OLEDB_TYPE_FUNCTION(LONG             ,DBTYPE_I4)     // DBTYPE_ERROR (SCODE)
    DEFINE_OLEDB_TYPE_FUNCTION(LARGE_INTEGER    ,DBTYPE_I8)     // DBTYPE_CY
    DEFINE_OLEDB_TYPE_FUNCTION(BYTE             ,DBTYPE_UI1)
    DEFINE_OLEDB_TYPE_FUNCTION(unsigned short   ,DBTYPE_UI2)
    DEFINE_OLEDB_TYPE_FUNCTION(unsigned int     ,DBTYPE_UI4)
    DEFINE_OLEDB_TYPE_FUNCTION(unsigned long    ,DBTYPE_UI4)
    DEFINE_OLEDB_TYPE_FUNCTION(ULARGE_INTEGER   ,DBTYPE_UI8)
    DEFINE_OLEDB_TYPE_FUNCTION(float            ,DBTYPE_R4)
    DEFINE_OLEDB_TYPE_FUNCTION(double           ,DBTYPE_R8)     // DBTYPE_DATE
    DEFINE_OLEDB_TYPE_FUNCTION(DECIMAL          ,DBTYPE_DECIMAL)
    DEFINE_OLEDB_TYPE_FUNCTION(DB_NUMERIC       ,DBTYPE_NUMERIC)
    DEFINE_OLEDB_TYPE_FUNCTION(VARIANT          ,DBTYPE_VARIANT)
    DEFINE_OLEDB_TYPE_FUNCTION(IDispatch*       ,DBTYPE_IDISPATCH)
    DEFINE_OLEDB_TYPE_FUNCTION(IUnknown*        ,DBTYPE_IUNKNOWN)
    DEFINE_OLEDB_TYPE_FUNCTION(GUID             ,DBTYPE_GUID)
    DEFINE_OLEDB_TYPE_FUNCTION(SAFEARRAY*       ,DBTYPE_ARRAY)
    DEFINE_OLEDB_TYPE_FUNCTION(DBVECTOR         ,DBTYPE_VECTOR)
    DEFINE_OLEDB_TYPE_FUNCTION(DBDATE           ,DBTYPE_DBDATE)
    DEFINE_OLEDB_TYPE_FUNCTION(DBTIME           ,DBTYPE_DBTIME)
    DEFINE_OLEDB_TYPE_FUNCTION(DBTIMESTAMP      ,DBTYPE_DBTIMESTAMP)
     DEFINE_OLEDB_TYPE_FUNCTION(FILETIME            ,DBTYPE_FILETIME)
    DEFINE_OLEDB_TYPE_FUNCTION(DBFILETIME        ,DBTYPE_DBFILETIME)
    DEFINE_OLEDB_TYPE_FUNCTION(PROPVARIANT        ,DBTYPE_PROPVARIANT)
    DEFINE_OLEDB_TYPE_FUNCTION(DB_VARNUMERIC    ,DBTYPE_VARNUMERIC)

// Internal structure containing the accessor handle and a flag
// indicating whether the data for the accessor is automatically
// retrieved
struct _ATL_ACCESSOR_INFO
{
    HACCESSOR   hAccessor;
    bool        bAutoAccessor;
};

class _CNoOutputColumns
{
public:
    static bool HasOutputColumns()
    {
        return false;
    }
    static ULONG _GetNumAccessors()
    {
        return 0;
    }
    static HRESULT _GetBindEntries(ULONG*, DBBINDING*, ULONG, bool*, BYTE* pBuffer = NULL)
    {
        pBuffer;
        return E_FAIL;
    }
};

class _CNoParameters
{
public:
    static bool HasParameters()
    {
        return false;
    }
    static HRESULT _GetParamEntries(ULONG*, DBBINDING*, BYTE* pBuffer = NULL)
    {
        pBuffer;
        return E_FAIL;
    }
};

class _CNoCommand
{
public:
    static HRESULT GetDefaultCommand(LPCTSTR* /*ppszCommand*/)
    {
        return S_OK;
    }
};

typedef _CNoOutputColumns   _OutputColumnsClass;
typedef _CNoParameters      _ParamClass;
typedef _CNoCommand         _CommandClass;

#define BEGIN_ACCESSOR_MAP(x, num) \
    public: \
    typedef x _classtype; \
    typedef x _OutputColumnsClass; \
    static ULONG _GetNumAccessors() { return num; } \
    static bool HasOutputColumns() { return true; } \
    /* If pBindings == NULL means we only return the column number */ \
    /* If pBuffer != NULL then it points to the accessor buffer and */ \
    /* we release any appropriate memory e.g. BSTR's or interface pointers */ \
    inline static HRESULT _GetBindEntries(ULONG* pColumns, DBBINDING *pBinding, ULONG nAccessor, bool* pAuto, BYTE* pBuffer = NULL) \
    { \
        ATLASSERT(pColumns != NULL); \
        DBPARAMIO eParamIO = DBPARAMIO_NOTPARAM; \
        ULONG nColumns = 0; \
        pBuffer;

#define BEGIN_ACCESSOR(num, bAuto) \
    if (nAccessor == num) \
    { \
        if (pBinding != NULL) \
            *pAuto = bAuto;

#define END_ACCESSOR() \
    } \
    else

#define END_ACCESSOR_MAP() \
        ; \
        *pColumns = nColumns; \
        return S_OK; \
    }

#define BEGIN_COLUMN_MAP(x) \
    BEGIN_ACCESSOR_MAP(x, 1) \
        BEGIN_ACCESSOR(0, true)

#define END_COLUMN_MAP() \
        END_ACCESSOR() \
    END_ACCESSOR_MAP()

#define offsetbuf(m) offsetof(_classtype, m)
#define _OLEDB_TYPE(data) _GetOleDBType(((_classtype*)0)->data)
#define _SIZE_TYPE(data) sizeof(((_classtype*)0)->data)

#define _COLUMN_ENTRY_CODE(nOrdinal, wType, nLength, nPrecision, nScale, dataOffset, lengthOffset, statusOffset) \
    if (pBuffer != NULL) \
    { \
        CAccessorBase::FreeType(wType, pBuffer + dataOffset); \
    } \
    else if (pBinding != NULL) \
    { \
        CAccessorBase::Bind(pBinding, nOrdinal, wType, nLength, nPrecision, nScale, eParamIO, \
            dataOffset, lengthOffset, statusOffset); \
        pBinding++; \
    } \
    nColumns++;

#define COLUMN_ENTRY_EX(nOrdinal, wType, nLength, nPrecision, nScale, data, length, status) \
    _COLUMN_ENTRY_CODE(nOrdinal, wType, nLength, nPrecision, nScale, offsetbuf(data), offsetbuf(length), offsetbuf(status))

#define COLUMN_ENTRY_TYPE(nOrdinal, wType, data) \
    COLUMN_ENTRY_TYPE_SIZE(nOrdinal, wType, _SIZE_TYPE(data), data)

#define COLUMN_ENTRY_TYPE_SIZE(nOrdinal, wType, nLength, data) \
    _COLUMN_ENTRY_CODE(nOrdinal, wType, nLength, 0, 0, offsetbuf(data), 0, 0)


// Standard macros where type and size is worked out
#define COLUMN_ENTRY(nOrdinal, data) \
    COLUMN_ENTRY_TYPE(nOrdinal, _OLEDB_TYPE(data), data)

#define COLUMN_ENTRY_LENGTH(nOrdinal, data, length) \
    _COLUMN_ENTRY_CODE(nOrdinal, _OLEDB_TYPE(data), _SIZE_TYPE(data), 0, 0, offsetbuf(data), offsetbuf(length), 0)

#define COLUMN_ENTRY_STATUS(nOrdinal, data, status) \
    _COLUMN_ENTRY_CODE(nOrdinal, _OLEDB_TYPE(data), _SIZE_TYPE(data), 0, 0, offsetbuf(data), 0, offsetbuf(status))

#define COLUMN_ENTRY_LENGTH_STATUS(nOrdinal, data, length, status) \
    _COLUMN_ENTRY_CODE(nOrdinal, _OLEDB_TYPE(data), _SIZE_TYPE(data), 0, 0, offsetbuf(data), offsetbuf(length), offsetbuf(status))


// Follow macros are used if precision and scale need to be specified
#define COLUMN_ENTRY_PS(nOrdinal, nPrecision, nScale, data) \
    _COLUMN_ENTRY_CODE(nOrdinal, _OLEDB_TYPE(data), _SIZE_TYPE(data), nPrecision, nScale, offsetbuf(data), 0, 0)

#define COLUMN_ENTRY_PS_LENGTH(nOrdinal, nPrecision, nScale, data, length) \
    _COLUMN_ENTRY_CODE(nOrdinal, _OLEDB_TYPE(data), _SIZE_TYPE(data), nPrecision, nScale, offsetbuf(data), offsetbuf(length), 0)

#define COLUMN_ENTRY_PS_STATUS(nOrdinal, nPrecision, nScale, data, status) \
    _COLUMN_ENTRY_CODE(nOrdinal, _OLEDB_TYPE(data), _SIZE_TYPE(data), nPrecision, nScale, offsetbuf(data), 0, offsetbuf(status))

#define COLUMN_ENTRY_PS_LENGTH_STATUS(nOrdinal, nPrecision, nScale, data, length, status) \
    _COLUMN_ENTRY_CODE(nOrdinal, _OLEDB_TYPE(data), _SIZE_TYPE(data), nPrecision, nScale, offsetbuf(data), offsetbuf(length), offsetbuf(status))


#define BOOKMARK_ENTRY(variable) \
    COLUMN_ENTRY_TYPE_SIZE(0, DBTYPE_BYTES, _SIZE_TYPE(variable##.m_rgBuffer), variable##.m_rgBuffer)

#define _BLOB_ENTRY_CODE(nOrdinal, IID, flags, dataOffset, statusOffset) \
    if (pBuffer != NULL) \
    { \
        CAccessorBase::FreeType(DBTYPE_IUNKNOWN, pBuffer + dataOffset); \
    } \
    else if (pBinding != NULL) \
    { \
        DBOBJECT* pObject = NULL; \
        ATLTRY(pObject = new DBOBJECT); \
        if (pObject == NULL) \
            return E_OUTOFMEMORY; \
        pObject->dwFlags = flags; \
        pObject->iid     = IID; \
        CAccessorBase::Bind(pBinding, nOrdinal, DBTYPE_IUNKNOWN, sizeof(IUnknown*), 0, 0, eParamIO, \
            dataOffset, 0, statusOffset, pObject); \
        pBinding++; \
    } \
    nColumns++;

#define BLOB_ENTRY(nOrdinal, IID, flags, data) \
    _BLOB_ENTRY_CODE(nOrdinal, IID, flags, offsetbuf(data), 0);

#define BLOB_ENTRY_STATUS(nOrdinal, IID, flags, data, status) \
    _BLOB_ENTRY_CODE(nOrdinal, IID, flags, offsetbuf(data), offsetbuf(status));

#define BEGIN_PARAM_MAP(x) \
    public: \
    typedef x _classtype; \
    typedef x _ParamClass; \
    static bool HasParameters() { return true; } \
    static HRESULT _GetParamEntries(ULONG* pColumns, DBBINDING *pBinding, BYTE* pBuffer = NULL) \
    { \
        ATLASSERT(pColumns != NULL); \
        DBPARAMIO eParamIO = DBPARAMIO_INPUT; \
        int nColumns = 0; \
        pBuffer;

#define END_PARAM_MAP() \
        *pColumns = nColumns; \
        return S_OK; \
    }

#define SET_PARAM_TYPE(type) \
    eParamIO = type;

#define DEFINE_COMMAND(x, szCommand) \
    typedef x _CommandClass; \
    static HRESULT GetDefaultCommand(LPCTSTR* ppszCommand) \
    { \
        *ppszCommand = szCommand; \
        return S_OK; \
    }


///////////////////////////////////////////////////////////////////////////
// class CDBErrorInfo

class CDBErrorInfo
{
public:
    // Use to get the number of error record when you want to explicitly check that
    // the passed interface set the error information
    HRESULT GetErrorRecords(IUnknown* pUnk, const IID& iid, ULONG* pcRecords)
    {
        CComPtr<ISupportErrorInfo> spSupportErrorInfo;
#ifdef __BORLANDC__
        HRESULT hr = pUnk->QueryInterface((void **) &spSupportErrorInfo);
#else
        HRESULT hr = pUnk->QueryInterface(&spSupportErrorInfo);
#endif
        if (FAILED(hr))
            return hr;

        hr = spSupportErrorInfo->InterfaceSupportsErrorInfo(iid);
        if (FAILED(hr))
            return hr;

        return GetErrorRecords(pcRecords);
    }
    // Use to get the number of error records
    HRESULT GetErrorRecords(ULONG* pcRecords)
    {
        ATLASSERT(pcRecords != NULL);
        HRESULT hr;
        m_spErrorInfo.Release();
        m_spErrorRecords.Release();
        hr = ::GetErrorInfo(0, &m_spErrorInfo);
        if (hr == S_FALSE)
            return E_FAIL;

        hr = m_spErrorInfo->QueryInterface(IID_IErrorRecords, (void**)&m_spErrorRecords);
        if (FAILED(hr))
        {
            // Well we got the IErrorInfo so we'll just treat that as
            // the one record
            *pcRecords = 1;
            return S_OK;
        }

        return m_spErrorRecords->GetRecordCount(pcRecords);
    }
    // Get the error information for the passed record number. GetErrorRecords must
    // be called before this function is called.
    HRESULT GetAllErrorInfo(ULONG ulRecordNum, LCID lcid, BSTR* pbstrDescription,
        BSTR* pbstrSource = NULL, GUID* pguid = NULL, DWORD* pdwHelpContext = NULL,
        BSTR* pbstrHelpFile = NULL) const
    {
        CComPtr<IErrorInfo> spErrorInfo;

        // If we have the IErrorRecords interface pointer then use it, otherwise
        // we'll just default to the IErrorInfo we have already retrieved in the call
        // to GetErrorRecords
        if (m_spErrorRecords != NULL)
        {
            HRESULT hr = m_spErrorRecords->GetErrorInfo(ulRecordNum, lcid, &spErrorInfo);
            if (FAILED(hr))
                return hr;
        }
        else
        {
            ATLASSERT(m_spErrorInfo != NULL);
            spErrorInfo = m_spErrorInfo;
        }

        if (pbstrDescription != NULL)
            spErrorInfo->GetDescription(pbstrDescription);

        if (pguid != NULL)
            spErrorInfo->GetGUID(pguid);

        if (pdwHelpContext != NULL)
            spErrorInfo->GetHelpContext(pdwHelpContext);

        if (pbstrHelpFile != NULL)
            spErrorInfo->GetHelpFile(pbstrHelpFile);

        if (pbstrSource != NULL)
            spErrorInfo->GetSource(pbstrSource);

        return S_OK;
    }
    // Get the error information for the passed record number
    HRESULT GetBasicErrorInfo(ULONG ulRecordNum, ERRORINFO* pErrorInfo) const
    {
        return m_spErrorRecords->GetBasicErrorInfo(ulRecordNum, pErrorInfo);
    }
    // Get the custom error object for the passed record number
    HRESULT GetCustomErrorObject(ULONG ulRecordNum, REFIID riid, IUnknown** ppObject) const
    {
        return m_spErrorRecords->GetCustomErrorObject(ulRecordNum, riid, ppObject);
    }
    // Get the IErrorInfo interface for the passed record number
    HRESULT GetErrorInfo(ULONG ulRecordNum, LCID lcid, IErrorInfo** ppErrorInfo) const
    {
        return m_spErrorRecords->GetErrorInfo(ulRecordNum, lcid, ppErrorInfo);
    }
    // Get the error parameters for the passed record number
    HRESULT GetErrorParameters(ULONG ulRecordNum, DISPPARAMS* pdispparams) const
    {
        return m_spErrorRecords->GetErrorParameters(ulRecordNum, pdispparams);
    }

// Implementation
    CComPtr<IErrorInfo>     m_spErrorInfo;
    CComPtr<IErrorRecords>  m_spErrorRecords;
};

#ifdef _DEBUG
inline void AtlTraceErrorRecords(HRESULT hrErr = S_OK)
{
    CDBErrorInfo ErrorInfo;
    ULONG        cRecords;
    HRESULT      hr;
    ULONG        i;
    CComBSTR     bstrDesc, bstrHelpFile, bstrSource;
    GUID         guid;
    DWORD        dwHelpContext;
    WCHAR        wszGuid[40];
    USES_CONVERSION;

    // If the user passed in an HRESULT then trace it
    if (hrErr != S_OK)
        ATLTRACE2(atlTraceDBClient, 0, _T("OLE DB Error Record dump for hr = 0x%x\n"), hrErr);

    LCID lcLocale = GetSystemDefaultLCID();

    hr = ErrorInfo.GetErrorRecords(&cRecords);
    if (FAILED(hr) && ErrorInfo.m_spErrorInfo == NULL)
    {
        ATLTRACE2(atlTraceDBClient, 0, _T("No OLE DB Error Information found: hr = 0x%x\n"), hr);
    }
    else
    {
        for (i = 0; i < cRecords; i++)
        {
            hr = ErrorInfo.GetAllErrorInfo(i, lcLocale, &bstrDesc, &bstrSource, &guid,
                                        &dwHelpContext, &bstrHelpFile);
            if (FAILED(hr))
            {
                ATLTRACE2(atlTraceDBClient, 0,
                    _T("OLE DB Error Record dump retrieval failed: hr = 0x%x\n"), hr);
                return;
            }
            StringFromGUID2(guid, wszGuid, sizeof(wszGuid) / sizeof(WCHAR));
            ATLTRACE2(atlTraceDBClient, 0,
                _T("Row #: %4d Source: \"%s\" Description: \"%s\" Help File: \"%s\" Help Context: %4d GUID: %s\n"),
                i, OLE2T(bstrSource), OLE2T(bstrDesc), OLE2T(bstrHelpFile), dwHelpContext, OLE2T(wszGuid));
            bstrSource.Empty();
            bstrDesc.Empty();
            bstrHelpFile.Empty();
        }
        ATLTRACE2(atlTraceDBClient, 0, _T("OLE DB Error Record dump end\n"));
    }
}
#else
inline void AtlTraceErrorRecords(HRESULT hrErr = S_OK)  { hrErr; }
#endif


///////////////////////////////////////////////////////////////////////////
// class CDBPropSet

class CDBPropSet : public tagDBPROPSET
{
public:
    CDBPropSet()
    {
        rgProperties    = NULL;
        cProperties     = 0;
    }
    CDBPropSet(const GUID& guid)
    {
        rgProperties    = NULL;
        cProperties     = 0;
        guidPropertySet = guid;
    }
    CDBPropSet(const CDBPropSet& propset)
    {
        InternalCopy(propset);
    }
    ~CDBPropSet()
    {
        for (ULONG i = 0; i < cProperties; i++)
            VariantClear(&rgProperties[i].vValue);

        CoTaskMemFree(rgProperties);
    }
    CDBPropSet& operator=(CDBPropSet& propset)
    {
        this->~CDBPropSet();
        InternalCopy(propset);
        return *this;
    }
    // Set the GUID of the property set this class represents.
    // Use if you didn't pass the GUID to the constructor.
    void SetGUID(const GUID& guid)
    {
        guidPropertySet = guid;
    }
    // Add the passed property to the property set
    bool AddProperty(DWORD dwPropertyID, const VARIANT& var)
    {
        HRESULT hr;
        if (!Add())
            return false;
        rgProperties[cProperties].dwPropertyID   = dwPropertyID;
        hr = ::VariantCopy(&(rgProperties[cProperties].vValue), const_cast<VARIANT*>(&var));
        if (FAILED(hr))
            return false;
        cProperties++;
        return true;
    }
    // Add the passed property to the property set
    bool AddProperty(DWORD dwPropertyID, LPCSTR szValue)
    {
        USES_CONVERSION;
        if (!Add())
            return false;
        rgProperties[cProperties].dwPropertyID   = dwPropertyID;
        rgProperties[cProperties].vValue.vt      = VT_BSTR;
        rgProperties[cProperties].vValue.bstrVal = SysAllocString(A2COLE(szValue));
        if (rgProperties[cProperties].vValue.bstrVal == NULL)
            return false;
        cProperties++;
        return true;
    }
    // Add the passed property to the property set
    bool AddProperty(DWORD dwPropertyID, LPCWSTR szValue)
    {
        USES_CONVERSION;
        if (!Add())
            return false;
        rgProperties[cProperties].dwPropertyID   = dwPropertyID;
        rgProperties[cProperties].vValue.vt      = VT_BSTR;
        rgProperties[cProperties].vValue.bstrVal = SysAllocString(W2COLE(szValue));
        if (rgProperties[cProperties].vValue.bstrVal == NULL)
            return false;
        cProperties++;
        return true;
    }
    // Add the passed property to the property set
    bool AddProperty(DWORD dwPropertyID, bool bValue)
    {
        if (!Add())
            return false;
        rgProperties[cProperties].dwPropertyID   = dwPropertyID;
        rgProperties[cProperties].vValue.vt      = VT_BOOL;
#pragma warning(disable: 4310) // cast truncates constant value
        rgProperties[cProperties].vValue.boolVal = (bValue) ? VARIANT_TRUE : VARIANT_FALSE;
#pragma warning(default: 4310)
        cProperties++;
        return true;
    }
    // Add the passed property to the property set
    bool AddProperty(DWORD dwPropertyID, BYTE bValue)
    {
        if (!Add())
            return false;
        rgProperties[cProperties].dwPropertyID  = dwPropertyID;
        rgProperties[cProperties].vValue.vt     = VT_UI1;
        rgProperties[cProperties].vValue.bVal   = bValue;
        cProperties++;
        return true;
    }
    // Add the passed property to the property set
    bool AddProperty(DWORD dwPropertyID, short nValue)
    {
        if (!Add())
            return false;
        rgProperties[cProperties].dwPropertyID  = dwPropertyID;
        rgProperties[cProperties].vValue.vt     = VT_I2;
        rgProperties[cProperties].vValue.iVal   = nValue;
        cProperties++;
        return true;
    }
    // Add the passed property to the property set
    bool AddProperty(DWORD dwPropertyID, long nValue)
    {
        if (!Add())
            return false;
        rgProperties[cProperties].dwPropertyID  = dwPropertyID;
        rgProperties[cProperties].vValue.vt     = VT_I4;
        rgProperties[cProperties].vValue.lVal   = nValue;
        cProperties++;
        return true;
    }
    // Add the passed property to the property set
    bool AddProperty(DWORD dwPropertyID, float fltValue)
    {
        if (!Add())
            return false;
        rgProperties[cProperties].dwPropertyID  = dwPropertyID;
        rgProperties[cProperties].vValue.vt     = VT_R4;
        rgProperties[cProperties].vValue.fltVal = fltValue;
        cProperties++;
        return true;
    }
    // Add the passed property to the property set
    bool AddProperty(DWORD dwPropertyID, double dblValue)
    {
        if (!Add())
            return false;
        rgProperties[cProperties].dwPropertyID  = dwPropertyID;
        rgProperties[cProperties].vValue.vt     = VT_R8;
        rgProperties[cProperties].vValue.dblVal = dblValue;
        cProperties++;
        return true;
    }
    // Add the passed property to the property set
    bool AddProperty(DWORD dwPropertyID, CY cyValue)
    {
        if (!Add())
            return false;
        rgProperties[cProperties].dwPropertyID  = dwPropertyID;
        rgProperties[cProperties].vValue.vt     = VT_CY;
        rgProperties[cProperties].vValue.cyVal  = cyValue;
        cProperties++;
        return true;
    }
// Implementation
    // Create memory to add a new property
    bool Add()
    {
        rgProperties = (DBPROP*)CoTaskMemRealloc(rgProperties, (cProperties + 1) * sizeof(DBPROP));
        if (rgProperties != NULL)
        {
            rgProperties[cProperties].dwOptions = DBPROPOPTIONS_REQUIRED;
            rgProperties[cProperties].colid     = DB_NULLID;
            rgProperties[cProperties].vValue.vt = VT_EMPTY;
            return true;
        }
        else
            return false;
    }
    // Copies in the passed value now it this value been cleared
    void InternalCopy(const CDBPropSet& propset)
    {
        cProperties     = propset.cProperties;
        guidPropertySet = propset.guidPropertySet;
        rgProperties    = (DBPROP*)CoTaskMemAlloc(cProperties * sizeof(DBPROP));
        if (rgProperties != NULL)
        {
            for (ULONG i = 0; i < cProperties; i++)
            {
                rgProperties[i].dwPropertyID = propset.rgProperties[i].dwPropertyID;
                rgProperties[i].dwOptions    = DBPROPOPTIONS_REQUIRED;
                rgProperties[i].colid        = DB_NULLID;
                rgProperties[i].vValue.vt    = VT_EMPTY;
                VariantCopy(&rgProperties[i].vValue, &propset.rgProperties[i].vValue);
            }
        }
        else
        {
            // The memory allocation failed so set the count
            // of properties to zero
            cProperties = 0;
        }
    }
};


///////////////////////////////////////////////////////////////////////////
// class CDBPropIDSet

class CDBPropIDSet : public tagDBPROPIDSET
{
// Constructors and Destructors
public:
    CDBPropIDSet()
    {
        rgPropertyIDs   = NULL;
        cPropertyIDs    = 0;
    }
    CDBPropIDSet(const GUID& guid)
    {
        rgPropertyIDs   = NULL;
        cPropertyIDs    = 0;
        guidPropertySet = guid;
    }
    CDBPropIDSet(const CDBPropIDSet& propidset)
    {
        InternalCopy(propidset);
    }
    ~CDBPropIDSet()
    {
        if (rgPropertyIDs != NULL)
            free(rgPropertyIDs);
    }
    CDBPropIDSet& operator=(CDBPropIDSet& propset)
    {
        this->~CDBPropIDSet();
        InternalCopy(propset);
        return *this;
    }
    // Set the GUID of the property ID set
    void SetGUID(const GUID& guid)
    {
        guidPropertySet = guid;
    }
    // Add a property ID to the set
    bool AddPropertyID(DBPROPID propid)
    {
        if (!Add())
            return false;
        rgPropertyIDs[cPropertyIDs] = propid;
        cPropertyIDs++;
        return true;
    }
// Implementation
    bool Add()
    {
        rgPropertyIDs = (DBPROPID*)realloc(rgPropertyIDs, (cPropertyIDs + 1) * sizeof(DBPROPID));
        return (rgPropertyIDs != NULL) ? true : false;
    }
    void InternalCopy(const CDBPropIDSet& propidset)
    {
        cPropertyIDs    = propidset.cPropertyIDs;
        guidPropertySet = propidset.guidPropertySet;
        rgPropertyIDs   = (DBPROPID*)malloc(cPropertyIDs * sizeof(DBPROPID));
        if (rgPropertyIDs != NULL)
        {
            for (ULONG i = 0; i < cPropertyIDs; i++)
                rgPropertyIDs[i] = propidset.rgPropertyIDs[i];
        }
        else
        {
            // The memory allocation failed so set the count
            // of properties to zero
            cPropertyIDs = 0;
        }
    }
};


///////////////////////////////////////////////////////////////////////////
// class CBookmarkBase

class ATL_NO_VTABLE CBookmarkBase
{
public:
    virtual ULONG GetSize() const = 0;
    virtual BYTE* GetBuffer() const = 0;
};


///////////////////////////////////////////////////////////////////////////
// class CBookmark

template <ULONG nSize = 0>
class CBookmark : public CBookmarkBase
{
public:
    virtual ULONG   GetSize() const { return nSize; }
    virtual BYTE*   GetBuffer() const { return (BYTE*)m_rgBuffer; }

// Implementation
    BYTE m_rgBuffer[nSize];
};


// Size of 0 means that the memory for the bookmark will be allocated
// at run time.
template <>
class CBookmark<0> : public CBookmarkBase
{
public:
    CBookmark()
    {
        m_nSize = 0;
        m_pBuffer = NULL;
    }
    CBookmark(ULONG nSize)
    {
        m_pBuffer = NULL;
        ATLTRY(m_pBuffer = new BYTE[nSize]);
        m_nSize = (m_pBuffer == NULL) ? 0 : nSize;
    }
    ~CBookmark()
    {
        delete [] m_pBuffer;
    }
    CBookmark& operator=(const CBookmark& bookmark)
    {
        SetBookmark(bookmark.GetSize(), bookmark.GetBuffer());
        return *this;
    }
    virtual ULONG GetSize() const { return m_nSize; }
    virtual BYTE* GetBuffer() const { return m_pBuffer; }
    // Sets the bookmark to the passed value
    HRESULT SetBookmark(ULONG nSize, BYTE* pBuffer)
    {
        ATLASSERT(pBuffer != NULL);
        delete [] m_pBuffer;
        m_pBuffer = NULL;
        ATLTRY(m_pBuffer = new BYTE[nSize]);
        if (m_pBuffer != NULL)
        {
            memcpy(m_pBuffer, pBuffer, nSize);
            m_nSize = nSize;
            return S_OK;
        }
        else
        {
            m_nSize = 0;
            return E_OUTOFMEMORY;
        }
    }
    ULONG   m_nSize;
    BYTE*   m_pBuffer;
};


///////////////////////////////////////////////////////////////////////////
// class CAccessorBase

class CAccessorBase
{
public:
    CAccessorBase()
    {
        m_pAccessorInfo  = NULL;
        m_nAccessors     = 0;
        m_pBuffer        = NULL;
    }
    void Close()
    {
        // If Close is called then ReleaseAccessors must have been
        // called first
        ATLASSERT(m_nAccessors == 0);
        ATLASSERT(m_pAccessorInfo == NULL);
    }
    // Get the number of accessors that have been created
    ULONG GetNumAccessors() const { return m_nAccessors; }
    // Get the handle of the passed accessor (offset from 0)
    HACCESSOR GetHAccessor(ULONG nAccessor) const
    {
        ATLASSERT(nAccessor<m_nAccessors);
        return m_pAccessorInfo[nAccessor].hAccessor;
    };
    // Called during Close to release the accessor information
    HRESULT ReleaseAccessors(IUnknown* pUnk)
    {
        ATLASSERT(pUnk != NULL);
        HRESULT hr = S_OK;
        if (m_nAccessors > 0)
        {
            CComPtr<IAccessor> spAccessor;
            hr = pUnk->QueryInterface(IID_IAccessor, (void**)&spAccessor);
            if (SUCCEEDED(hr))
            {
                ATLASSERT(m_pAccessorInfo != NULL);
                for (ULONG i = 0; i < m_nAccessors; i++)
                    spAccessor->ReleaseAccessor(m_pAccessorInfo[i].hAccessor, NULL);
            }
            m_nAccessors = 0;
            delete [] m_pAccessorInfo;
            m_pAccessorInfo = NULL;
        }
        return hr;
    }
    // Returns true or false depending upon whether data should be
    // automatically retrieved for the passed accessor.
    bool IsAutoAccessor(ULONG nAccessor) const
    {
        ATLASSERT(nAccessor < m_nAccessors);
        ATLASSERT(m_pAccessorInfo != NULL);
        return m_pAccessorInfo[nAccessor].bAutoAccessor;
    }

// Implementation
    // Used by the rowset class to find out where to place the data
    BYTE* GetBuffer() const
    {
        return m_pBuffer;
    }
    // Set the buffer that is used to retrieve the data
    void SetBuffer(BYTE* pBuffer)
    {
        m_pBuffer = pBuffer;
    }

    // Allocate internal memory for the passed number of accessors
    HRESULT AllocateAccessorMemory(int nAccessors)
    {
        // Can't be called twice without calling ReleaseAccessors first
        ATLASSERT(m_pAccessorInfo == NULL);
        m_nAccessors    = nAccessors;
        m_pAccessorInfo = NULL;
        ATLTRY(m_pAccessorInfo = new _ATL_ACCESSOR_INFO[nAccessors]);
        if (m_pAccessorInfo == NULL)
            return E_OUTOFMEMORY;
        else
            return S_OK;
    }
    // BindParameters will be overriden if parameters are used
    HRESULT BindParameters(HACCESSOR*, ICommand*, void**) { return S_OK; }

    // Create an accessor for the passed binding information. The created accessor is
    // returned through the pHAccessor parameter.
    static HRESULT BindEntries(DBBINDING* pBindings, int nColumns, HACCESSOR* pHAccessor,
        ULONG nSize, IAccessor* pAccessor)
    {
        ATLASSERT(pBindings  != NULL);
        ATLASSERT(pHAccessor != NULL);
        ATLASSERT(pAccessor  != NULL);
        HRESULT hr;
        int i;
        DWORD dwAccessorFlags = (pBindings->eParamIO == DBPARAMIO_NOTPARAM) ?
            DBACCESSOR_ROWDATA : DBACCESSOR_PARAMETERDATA;

#ifdef _DEBUG
        // In debug builds we will retrieve the status flags and trace out
        // any errors that may occur.
        DBBINDSTATUS* pStatus = NULL;
        ATLTRY(pStatus = new DBBINDSTATUS[nColumns]);
        hr = pAccessor->CreateAccessor(dwAccessorFlags, nColumns,
            pBindings, nSize, pHAccessor, pStatus);
        if (FAILED(hr) && pStatus != NULL)
        {
            for (i=0; i<nColumns; i++)
            {
                if (pStatus[i] != DBBINDSTATUS_OK)
                    ATLTRACE2(atlTraceDBClient, 0, _T("Binding entry %d failed. Status: %d\n"), i, pStatus[i]);
            }
        }
        delete [] pStatus;
#else
        hr = pAccessor->CreateAccessor(dwAccessorFlags, nColumns,
            pBindings, nSize, pHAccessor, NULL);
#endif
        for (i=0; i<nColumns; i++)
            delete pBindings[i].pObject;

        return hr;
    }
    // Set up the binding structure pointed to by pBindings based upon
    // the other passed parameters.
    static void Bind(DBBINDING* pBinding, ULONG nOrdinal, DBTYPE wType,
        ULONG nLength, BYTE nPrecision, BYTE nScale, DBPARAMIO eParamIO,
        ULONG nDataOffset, ULONG nLengthOffset = NULL, ULONG nStatusOffset = NULL,
        DBOBJECT* pdbobject = NULL)
    {
        ATLASSERT(pBinding != NULL);

        // If we are getting a pointer to the data then let the provider
        // own the memory
        if (wType & DBTYPE_BYREF)
            pBinding->dwMemOwner = DBMEMOWNER_PROVIDEROWNED;
        else
            pBinding->dwMemOwner = DBMEMOWNER_CLIENTOWNED;

        pBinding->pObject   = pdbobject;

        pBinding->eParamIO      = eParamIO;
        pBinding->iOrdinal      = nOrdinal;
        pBinding->wType         = wType;
        pBinding->bPrecision    = nPrecision;
        pBinding->bScale        = nScale;
        pBinding->dwFlags       = 0;

        pBinding->obValue       = nDataOffset;
        pBinding->obLength      = 0;
        pBinding->obStatus      = 0;
        pBinding->pTypeInfo     = NULL;
        pBinding->pBindExt      = NULL;
        pBinding->cbMaxLen      = nLength;

        pBinding->dwPart = DBPART_VALUE;
        if (nLengthOffset != NULL)
        {
            pBinding->dwPart |= DBPART_LENGTH;
            pBinding->obLength = nLengthOffset;
        }
        if (nStatusOffset != NULL)
        {
            pBinding->dwPart |= DBPART_STATUS;
            pBinding->obStatus = nStatusOffset;
        }
    }

    // Free memory if appropriate
    static inline void FreeType(DBTYPE wType, BYTE* pValue, IRowset* pRowset = NULL)
    {
        switch (wType)
        {
            case DBTYPE_BSTR:
                SysFreeString(*((BSTR*)pValue));
            break;
            case DBTYPE_VARIANT:
                VariantClear((VARIANT*)pValue);
            break;
            case DBTYPE_IUNKNOWN:
            case DBTYPE_IDISPATCH:
                (*(IUnknown**)pValue)->Release();
            break;
            case DBTYPE_ARRAY:
                SafeArrayDestroy((SAFEARRAY*)pValue);
            break;

            case DBTYPE_HCHAPTER:
                CComQIPtr<IChapteredRowset> spChapteredRowset = pRowset;
                if (spChapteredRowset != NULL)
                    spChapteredRowset->ReleaseChapter(*(HCHAPTER*)pValue, NULL);
            break;
        }
        if ((wType & DBTYPE_VECTOR) && ~(wType & DBTYPE_BYREF))
            CoTaskMemFree(((DBVECTOR*)pValue)->ptr);
    }

    _ATL_ACCESSOR_INFO* m_pAccessorInfo;
    ULONG               m_nAccessors;
    BYTE*               m_pBuffer;
};

///////////////////////////////////////////////////////////////////////////
// class CRowset

class CRowset
{
// Constructors and Destructors
public:
    CRowset()
    {
        m_pAccessor = NULL;
        m_hRow      = NULL;
    }
    CRowset(IRowset* pRowset)
    {
        m_spRowset  = pRowset;
        CRowset();
    }
    ~CRowset()
    {
        Close();
    }
    // Release any retrieved row handles and then release the rowset
    void Close()
    {
        if (m_spRowset != NULL)
        {
            ReleaseRows();
            m_spRowset.Release();
            m_spRowsetChange.Release();
        }
    }
    // Addref the current row
    HRESULT AddRefRows()
    {
        ATLASSERT(m_spRowset != NULL);
        return m_spRowset->AddRefRows(1, &m_hRow, NULL, NULL);
    }
    // Release the current row
    HRESULT ReleaseRows()
    {
        ATLASSERT(m_spRowset != NULL);
        HRESULT hr = S_OK;

        if (m_hRow != NULL)
        {
            hr = m_spRowset->ReleaseRows(1, &m_hRow, NULL, NULL, NULL);
            m_hRow = NULL;
        }
        return hr;
    }
    // Compare two bookmarks with each other
    HRESULT Compare(const CBookmarkBase& bookmark1, const CBookmarkBase& bookmark2,
        DBCOMPARE* pComparison) const
    {
        ATLASSERT(m_spRowset != NULL);
        CComPtr<IRowsetLocate> spLocate;
        HRESULT hr = m_spRowset.QueryInterface(&spLocate);
        if (FAILED(hr))
            return hr;

        return spLocate->Compare(NULL, bookmark1.GetSize(), bookmark1.GetBuffer(),
            bookmark2.GetSize(), bookmark2.GetBuffer(), pComparison);
    }
    // Compare the passed hRow with the current row
    HRESULT IsSameRow(HROW hRow) const
    {
        ATLASSERT(m_spRowset != NULL);
        CComPtr<IRowsetIdentity> spRowsetIdentity;
        HRESULT hr = m_spRowset.QueryInterface(&spRowsetIdentity);
        if (FAILED(hr))
            return hr;

        return spRowsetIdentity->IsSameRow(m_hRow, hRow);
    }
    // Move to the previous record
    HRESULT MovePrev()
    {
        return MoveNext(-2, true);
    }
    // Move to the next record
    HRESULT MoveNext()
    {
        return MoveNext(0, true);
    }
    // Move lSkip records forward or backward
    HRESULT MoveNext(LONG lSkip, bool bForward)
    {
        HRESULT hr;
        ULONG ulRowsFetched = 0;

        // Check the data was opened successfully and the accessor
        // has been set.
        ATLASSERT(m_spRowset != NULL);
        ATLASSERT(m_pAccessor != NULL);

        // Release a row if one is already around
        ReleaseRows();

        // Get the row handle
        HROW* phRow = &m_hRow;
        hr = m_spRowset->GetNextRows(NULL, lSkip, (bForward) ? 1 : -1, &ulRowsFetched, &phRow);
        if (hr != S_OK)
            return hr;

        // Get the data
        hr = GetData();
        if (FAILED(hr))
        {
            ATLTRACE2(atlTraceDBClient, 0, _T("GetData failed - HRESULT = 0x%X\n"),hr);
            ReleaseRows();
        }
        return hr;
    }
    // Move to the first record
    HRESULT MoveFirst()
    {
        HRESULT hr;

        // Check the data was opened successfully and the accessor
        // has been set.
        ATLASSERT(m_spRowset != NULL);
        ATLASSERT(m_pAccessor != NULL);

        // Release a row if one is already around
        ReleaseRows();

        hr = m_spRowset->RestartPosition(NULL);
        if (FAILED(hr))
            return hr;

        // Get the data
        return MoveNext();
    }
    // Move to the last record
    HRESULT MoveLast()
    {
        // Check the data was opened successfully and the accessor
        // has been set.
        ATLASSERT(m_spRowset != NULL);
        ATLASSERT(m_pAccessor != NULL);

        // Release a row if one is already around
        ReleaseRows();

        HRESULT hr;
        ULONG ulRowsFetched = 0;
        HROW* phRow = &m_hRow;
        // Restart the rowset position and then move backwards
        m_spRowset->RestartPosition(NULL);
        hr = m_spRowset->GetNextRows(NULL, -1, 1, &ulRowsFetched, &phRow);
        if (hr != S_OK)
            return hr;

        // Get the data
        hr = GetData();
        if (FAILED(hr))
        {
            ATLTRACE2(atlTraceDBClient, 0, _T("GetData from MoveLast failed - HRESULT = 0x%X\n"),hr);
            ReleaseRows();
        }

        return S_OK;
    }
    // Move to the passed bookmark
    HRESULT MoveToBookmark(const CBookmarkBase& bookmark, LONG lSkip = 0)
    {
        // Check the data was opened successfully and the accessor
        // has been set.
        ATLASSERT(m_spRowset != NULL);
        ATLASSERT(m_pAccessor != NULL);

        CComPtr<IRowsetLocate> spLocate;
        HRESULT hr = m_spRowset.QueryInterface(&spLocate);
        if (FAILED(hr))
            return hr;

        // Release a row if one is already around
        ReleaseRows();

        ULONG ulRowsFetched = 0;
        HROW* phRow = &m_hRow;
        hr = spLocate->GetRowsAt(NULL, NULL, bookmark.GetSize(), bookmark.GetBuffer(),
            lSkip, 1, &ulRowsFetched, &phRow);
        // Note we're not using SUCCEEDED here, because we could get DB_S_ENDOFROWSET
        if (hr != S_OK)
            return hr;

        // Get the data
        hr = GetData();
        if (FAILED(hr))
        {
            ATLTRACE2(atlTraceDBClient, 0, _T("GetData from Bookmark failed - HRESULT = 0x%X\n"),hr);
            ReleaseRows();
        }

        return S_OK;
    }
    // Get the data for the current record
    HRESULT GetData()
    {
        HRESULT hr = S_OK;
        ATLASSERT(m_pAccessor != NULL);

        ULONG nAccessors = m_pAccessor->GetNumAccessors();
        for (ULONG i=0; i<nAccessors; i++)
        {
            if (m_pAccessor->IsAutoAccessor(i))
            {
                hr = GetData(i);
                if (FAILED(hr))
                    return hr;
            }
        }
        return hr;
    }
    // Get the data for the passed accessor. Use for a non-auto accessor
    HRESULT GetData(int nAccessor)
    {
        ATLASSERT(m_spRowset != NULL);
        ATLASSERT(m_pAccessor != NULL);
        ATLASSERT(m_hRow != NULL);

        // Note that we are using the specified buffer if it has been set,
        // otherwise we use the accessor for the data.
        return m_spRowset->GetData(m_hRow, m_pAccessor->GetHAccessor(nAccessor), m_pAccessor->GetBuffer());
    }
    // Get the data for the passed accessor. Use for a non-auto accessor
    HRESULT GetDataHere(int nAccessor, void* pBuffer)
    {
        ATLASSERT(m_spRowset != NULL);
        ATLASSERT(m_pAccessor != NULL);
        ATLASSERT(m_hRow != NULL);

        // Note that we are using the specified buffer if it has been set,
        // otherwise we use the accessor for the data.
        return m_spRowset->GetData(m_hRow, m_pAccessor->GetHAccessor(nAccessor), pBuffer);
    }
    HRESULT GetDataHere(void* pBuffer)
    {
        HRESULT hr = S_OK;

        ULONG nAccessors = m_pAccessor->GetNumAccessors();
        for (ULONG i=0; i<nAccessors; i++)
        {
            hr = GetDataHere(i, pBuffer);
            if (FAILED(hr))
                return hr;
        }
        return hr;
    }

    // Insert the current record
    HRESULT Insert(int nAccessor = 0, bool bGetHRow = false)
    {
        ATLASSERT(m_pAccessor != NULL);
        HRESULT hr;
        if (m_spRowsetChange != NULL)
        {
            HROW* pHRow;
            if (bGetHRow)
            {
                ReleaseRows();
                pHRow = &m_hRow;
            }
            else
                pHRow = NULL;

            hr = m_spRowsetChange->InsertRow(NULL, m_pAccessor->GetHAccessor(nAccessor),
                    m_pAccessor->GetBuffer(), pHRow);

        }
        else
            hr = E_NOINTERFACE;

        return hr;
    }
    // Delete the current record
    HRESULT Delete() const
    {
        ATLASSERT(m_pAccessor != NULL);
        HRESULT hr;
        if (m_spRowsetChange != NULL)
            hr = m_spRowsetChange->DeleteRows(NULL, 1, &m_hRow, NULL);
        else
            hr = E_NOINTERFACE;

        return hr;
    }
    // Update the current record
    HRESULT SetData() const
    {
        ATLASSERT(m_pAccessor != NULL);
        HRESULT hr = S_OK;

        ULONG nAccessors = m_pAccessor->GetNumAccessors();
        for (ULONG i=0; i<nAccessors; i++)
        {
            hr = SetData(i);
            if (FAILED(hr))
                return hr;
        }
        return hr;
    }
    // Update the current record with the data in the passed accessor
    HRESULT SetData(int nAccessor) const
    {
        ATLASSERT(m_pAccessor != NULL);
        HRESULT hr;
        if (m_spRowsetChange != NULL)
        {
            hr = m_spRowsetChange->SetData(m_hRow, m_pAccessor->GetHAccessor(nAccessor),
                m_pAccessor->GetBuffer());
        }
        else
            hr = E_NOINTERFACE;

        return hr;
    }

    // Get the data most recently fetched from or transmitted to the data source.
    // Does not get values based on pending changes.
    HRESULT GetOriginalData()
    {
        ATLASSERT(m_spRowset != NULL);
        ATLASSERT(m_pAccessor != NULL);

        HRESULT hr = S_OK;
        CComPtr<IRowsetUpdate> spRowsetUpdate;
        hr = m_spRowset->QueryInterface(&spRowsetUpdate);
        if (FAILED(hr))
            return hr;

        ULONG nAccessors = m_pAccessor->GetNumAccessors();
        for (ULONG i = 0; i < nAccessors; i++)
        {
            hr = spRowsetUpdate->GetOriginalData(m_hRow, m_pAccessor->GetHAccessor(i), m_pAccessor->GetBuffer());
            if (FAILED(hr))
                return hr;
        }
        return hr;
    }
    // Get the status of the current row
    HRESULT GetRowStatus(DBPENDINGSTATUS* pStatus) const
    {
        ATLASSERT(m_spRowset != NULL);
        ATLASSERT(pStatus != NULL);

        CComPtr<IRowsetUpdate> spRowsetUpdate;
        HRESULT hr = m_spRowset->QueryInterface(&spRowsetUpdate);
        if (FAILED(hr))
            return hr;

        return spRowsetUpdate->GetRowStatus(NULL, 1, &m_hRow, pStatus);
    }
    // Undo any changes made to the current row since it was last fetched or Update
    // was called for it
    HRESULT Undo(ULONG* pcRows = NULL, HROW* phRow = NULL, DBROWSTATUS* pStatus = NULL)
    {
        ATLASSERT(m_spRowset != NULL);

        CComPtr<IRowsetUpdate> spRowsetUpdate;
        HRESULT hr = m_spRowset->QueryInterface(&spRowsetUpdate);
        if (FAILED(hr))
            return hr;

        HROW*           prgRows;
        DBROWSTATUS*    pRowStatus;
        if (phRow != NULL)
            hr = spRowsetUpdate->Undo(NULL, 1, &m_hRow, pcRows, &prgRows, &pRowStatus);
        else
            hr = spRowsetUpdate->Undo(NULL, 1, &m_hRow, pcRows, NULL, &pRowStatus);
        if (FAILED(hr))
            return hr;

        if (phRow != NULL)
        {
            *phRow = *prgRows;
            CoTaskMemFree(prgRows);
        }
        if (pStatus != NULL)
            *pStatus = *pRowStatus;

        CoTaskMemFree(pRowStatus);
        return hr;
    }
    // Transmits any pending changes made to a row since it was last fetched or Update was
    // called for it. Also see SetData.
    HRESULT Update(ULONG* pcRows = NULL, HROW* phRow = NULL, DBROWSTATUS* pStatus = NULL)
    {
        ATLASSERT(m_spRowset != NULL);

        CComPtr<IRowsetUpdate> spRowsetUpdate;
        HRESULT hr = m_spRowset->QueryInterface(&spRowsetUpdate);
        if (FAILED(hr))
            return hr;

        HROW*           prgRows;
        DBROWSTATUS*    pRowStatus;
        if (phRow != NULL)
            hr = spRowsetUpdate->Update(NULL, 1, &m_hRow, pcRows, &prgRows, &pRowStatus);
        else
            hr = spRowsetUpdate->Update(NULL, 1, &m_hRow, pcRows, NULL, &pRowStatus);
        if (FAILED(hr))
            return hr;

        if (phRow != NULL)
        {
            *phRow = *prgRows;
            CoTaskMemFree(prgRows);
        }
        if (pStatus != NULL)
            *pStatus = *pRowStatus;

        CoTaskMemFree(pRowStatus);
        return hr;
    }

    // Get the approximate position of the row corresponding to the passed bookmark
    HRESULT GetApproximatePosition(const CBookmarkBase* pBookmark, ULONG* pPosition, ULONG* pcRows)
    {
        ATLASSERT(m_spRowset != NULL);

        CComPtr<IRowsetScroll> spRowsetScroll;
        HRESULT hr = m_spRowset->QueryInterface(&spRowsetScroll);
        if (SUCCEEDED(hr))
        {
            if (pBookmark != NULL)
                hr = spRowsetScroll->GetApproximatePosition(NULL, pBookmark->GetSize(), pBookmark->GetBuffer(),
                        pPosition, pcRows);
            else
                hr = spRowsetScroll->GetApproximatePosition(NULL, 0, NULL, pPosition, pcRows);

        }
        return hr;

    }
    // Move to a fractional position in the rowset
    HRESULT MoveToRatio(ULONG nNumerator, ULONG nDenominator, bool bForward = true)
    {
        ATLASSERT(m_spRowset != NULL);
        ULONG   nRowsFetched;

        CComPtr<IRowsetScroll> spRowsetScroll;
        HRESULT hr = m_spRowset->QueryInterface(&spRowsetScroll);
        if (FAILED(hr))
            return hr;

        ReleaseRows();
        HROW* phRow = &m_hRow;
        hr = spRowsetScroll->GetRowsAtRatio(NULL, NULL, nNumerator, nDenominator, (bForward) ? 1 : -1,
            &nRowsFetched, &phRow);
        // Note we're not using SUCCEEDED here, because we could get DB_S_ENDOFROWSET
        if (hr == S_OK)
            hr = GetData();

        return hr;
    }

// Implementation
    static const IID& GetIID()
    {
        return IID_IRowset;
    }
    IRowset* GetInterface() const
    {
        return m_spRowset;
    }
    IRowset** GetInterfacePtr()
    {
        return &m_spRowset;
    }
    void SetupOptionalRowsetInterfaces()
    {
        // Cache IRowsetChange if available
        if (m_spRowset != NULL)
            m_spRowset->QueryInterface(&m_spRowsetChange);
    }
    HRESULT BindFinished() const { return S_OK; }
    void    SetAccessor(CAccessorBase* pAccessor)
    {
        m_pAccessor = pAccessor;
    }

    CComPtr<IRowset>        m_spRowset;
    CComPtr<IRowsetChange>  m_spRowsetChange;
    CAccessorBase*          m_pAccessor;
    HROW                    m_hRow;
};


///////////////////////////////////////////////////////////////////////////
// class CBulkRowset

class CBulkRowset : public CRowset
{
public:
    CBulkRowset()
    {
        // Default the number of rows to bulk fetch to 10
        m_nRows = 10;
        m_hr    = S_OK;
        m_phRow = NULL;
    }
    CBulkRowset::~CBulkRowset()
    {
        Close();

        delete [] m_phRow;
    }
    // Set the number of row handles that will be retrieved in each
    // bulk row fetch. The default is 10 and this function must be called
    // before Open if you wish to change it.
    void SetRows(ULONG nRows)
    {
        // This function must be called before the memory is allocated
        // during binding
        ATLASSERT(m_phRow == NULL);
        m_nRows = nRows;
    }
    // AddRef all the currently retrieved row handles
    HRESULT AddRefRows()
    {
        ATLASSERT(m_spRowset != NULL);
        return m_spRowset->AddRefRows(m_nCurrentRows, m_phRow, NULL, NULL);
    }
    // Release all the currently retrieved row handles
    HRESULT ReleaseRows()
    {
        ATLASSERT(m_spRowset != NULL);
        // We're going to Release the rows so reset the current row position
        m_nCurrentRow = 0;
        m_hRow        = NULL;
        return m_spRowset->ReleaseRows(m_nCurrentRows, m_phRow, NULL, NULL, NULL);
    }
    // Move to the first record
    HRESULT MoveFirst()
    {
        ATLASSERT(m_spRowset != NULL);
        ReleaseRows();

        // Cause MoveNext to perform a new bulk fetch
        m_nCurrentRow  = m_nRows;

        HRESULT hr = m_spRowset->RestartPosition(NULL);
        if (FAILED(hr))
            return hr;

        // Get the data
        return MoveNext();
    }
    // Move to the next record
    HRESULT MoveNext()
    {
        ATLASSERT(m_spRowset != NULL);
        ATLASSERT(m_phRow    != NULL);

        // Move to the next record in the buffer
        m_nCurrentRow++;

        // Have we reached the end of the buffer?
        if (m_nCurrentRow >= m_nCurrentRows)
        {
            // If we've reached the end of the buffer and we had a non S_OK HRESULT from
            // the last call to GetNextRows then return that HRESULT now.
            if (m_hr != S_OK)
                return m_hr;

            // We've finished with these rows so we need some more
            // First release any HROWs that we have
            ReleaseRows();

            m_hr = m_spRowset->GetNextRows(NULL, 0, m_nRows, &m_nCurrentRows, &m_phRow);
            // If we have an error HRESULT or we haven't retrieved any rows then return
            // the HRESULT now.
            if (FAILED(m_hr) || m_nCurrentRows == 0)
                return m_hr;
        }

        // Get the data for the current row
        m_hRow = m_phRow[m_nCurrentRow];
        return GetData();
    }
    // Move to the previous record
    HRESULT MovePrev()
    {
        ATLASSERT(m_spRowset != NULL);
        ATLASSERT(m_phRow    != NULL);

        // Check if we're at the start of the block
        if (m_nCurrentRow == 0)
        {
            ReleaseRows();

            // Go back the amount of rows in the block - 1 and fetch forward
            m_hr = m_spRowset->GetNextRows(NULL, -(LONG)m_nRows-1, m_nRows, &m_nCurrentRows, &m_phRow);

            // Set the current record to the end of the new block
            m_nCurrentRow = m_nCurrentRows - 1;

            // If we have an error HRESULT or we haven't retrieved any rows then return
            // the HRESULT now.
            if (FAILED(m_hr) || m_nCurrentRows == 0)
                return m_hr;
        }
        else
        {
            // Move back a row in the block
            m_nCurrentRow--;
        }

        // Get the data for the current row
        m_hRow = m_phRow[m_nCurrentRow];
        return GetData();
    }
    // Move to the last record
    HRESULT MoveLast()
    {
        ReleaseRows();
        return CRowset::MoveLast();
    }
    // Move to the passed bookmark
    HRESULT MoveToBookmark(const CBookmarkBase& bookmark, LONG lSkip = 0)
    {
        ATLASSERT(m_spRowset != NULL);
        CComPtr<IRowsetLocate> spLocate;
        HRESULT hr = m_spRowset->QueryInterface(&spLocate);
        if (FAILED(hr))
            return hr;

        ReleaseRows();
        m_hr = spLocate->GetRowsAt(NULL, NULL, bookmark.GetSize(), bookmark.GetBuffer(),
            lSkip, m_nRows, &m_nCurrentRows, &m_phRow);
        if (m_hr != S_OK || m_nCurrentRows == 0)
            return m_hr;

        // Get the data
        m_hRow = m_phRow[m_nCurrentRow];
        return GetData();
    }
    // Move to a fractional position in the rowset
    HRESULT MoveToRatio(ULONG nNumerator, ULONG nDenominator)
    {
        ATLASSERT(m_spRowset != NULL);

        CComPtr<IRowsetScroll> spRowsetScroll;
        HRESULT hr = m_spRowset->QueryInterface(&spRowsetScroll);
        if (FAILED(hr))
            return hr;

        ReleaseRows();
        m_hr = spRowsetScroll->GetRowsAtRatio(NULL, NULL, nNumerator, nDenominator, m_nRows, &m_nCurrentRows, &m_phRow);
        if (m_hr != S_OK || m_nCurrentRows == 0)
            return m_hr;

        // Get the data
        m_hRow = m_phRow[m_nCurrentRow];
        return GetData();
    }
    // Insert the current record
    HRESULT Insert(int nAccessor = 0, bool bGetHRow = false)
    {
        ReleaseRows();
        return CRowset::Insert(nAccessor, bGetHRow);
    }

// Implementation
    HRESULT BindFinished()
    {
        // No rows in the buffer yet
        m_nCurrentRows = 0;
        // Cause MoveNext to automatically perform a new bulk fetch the first time
        m_nCurrentRow  = m_nRows;

        m_phRow = NULL;
        ATLTRY(m_phRow = new HROW[m_nRows]);
        if (m_phRow == NULL)
            return E_OUTOFMEMORY;

        return S_OK;
    }

    HRESULT m_hr;           // HRESULT to return from MoveNext at end of buffer
    HROW*   m_phRow;        // Pointer to array of HROWs for each row in buffer
    ULONG   m_nRows;        // Number of rows that will fit in the buffer
    ULONG   m_nCurrentRows; // Number of rows currently in the buffer
    ULONG   m_nCurrentRow;
};

///////////////////////////////////////////////////////////////////////////
// class CArrayRowset
//
// Allows you to access a rowset with an array syntax

template <class T, class TRowset = CRowset>
class CArrayRowset :
    public CVirtualBuffer<T>,
    public TRowset
{
public:
    CArrayRowset(int nMax = 100000) : CVirtualBuffer<T>(nMax)
    {
        m_nRowsRead = 0;
    }
    T& operator[](int nRow)
    {
        ATLASSERT(nRow >= 0);
        HRESULT hr;
        T* m_pCurrent = m_pBase + m_nRowsRead;

        // Retrieve the row if we haven't retrieved it already
        while ((ULONG)nRow >= m_nRowsRead)
        {
            m_pAccessor->SetBuffer((BYTE*)m_pCurrent);
            __try
            {
                // Get the row
                hr = MoveNext();
                if (hr != S_OK)
                {
                    *((char*)0) = 0; // Force exception
                }
            }
            __except(Except(GetExceptionInformation()))
            {
            }
            m_nRowsRead++;
            m_pCurrent++;
        }

        return *(m_pBase + nRow);
    }

    HRESULT Snapshot()
    {
        ATLASSERT(m_nRowsRead == 0);
        ATLASSERT(m_spRowset != NULL);
        HRESULT hr = MoveFirst();
        if (FAILED(hr))
            return hr;
        do
        {
            Write(*(T*)m_pAccessor->GetBuffer());
            m_nRowsRead++;
            hr = MoveNext();
        } while (SUCCEEDED(hr) &&  hr != DB_S_ENDOFROWSET);

        return (hr == DB_S_ENDOFROWSET) ? S_OK : hr;
    }


// Implementation
    ULONG   m_nRowsRead;
};

// Used when you don't need any parameters or output columns
class CNoAccessor
{
public:
    // We don't need any typedef's here as the default
    // global typedef is not to have any parameters and
    // output columns.
    HRESULT BindColumns(IUnknown*) { return S_OK; }
    HRESULT BindParameters(HACCESSOR*, ICommand*, void**) { return S_OK; }
    void    Close() { }
    HRESULT ReleaseAccessors(IUnknown*) { return S_OK; }
};

// Used when a rowset will not be returned from the command
class CNoRowset
{
public:
    HRESULT             BindFinished() { return S_OK; }
    void                Close() { }
    static const IID&   GetIID() { return IID_NULL; }
    IRowset*            GetInterface() const { return NULL; }
    IRowset**           GetInterfacePtr() { return NULL; }
    void                SetAccessor(void*) { }
    void                SetupOptionalRowsetInterfaces() { }
};

///////////////////////////////////////////////////////////////////////////
// class CAccessor

// T is the class that contains the data that will be accessed.
template <class T>
class CAccessor :
    public T,
    public CAccessorBase
{
public:
// Implementation
    // Free's any columns in the current record that need to be freed.
    // E.g. Calls SysFreeString on any BSTR's and Release on any interfaces.
    void FreeRecordMemory(IRowset* /* pRowset */)
    {
        ULONG nColumns;
        ULONG i;

        for (i = 0; i < GetNumAccessors(); i++)
        {
            // Passing in m_pBuffer tells the column entry maps to free the
            // memory for the types if appropriate
            _GetBindEntries(&nColumns, NULL, i, NULL, m_pBuffer);
        }
    }
    HRESULT BindColumns(IUnknown* pUnk)
    {
        HRESULT hr;
        ULONG   nAccessors;
        ULONG   nSize;
        nAccessors = _OutputColumnsClass::_GetNumAccessors();

        SetBuffer((BYTE*)this);

        nSize = sizeof(T);
        hr = BindAccessors(nAccessors, nSize, pUnk);
        return hr;
    }
    HRESULT BindAccessors(ULONG nAccessors, ULONG nSize, IUnknown* pUnk)
    {
        ATLASSERT(pUnk != NULL);
        HRESULT hr;

        CComPtr<IAccessor> spAccessor;
        hr = pUnk->QueryInterface(&spAccessor);
        if (SUCCEEDED(hr))
        {
            // Allocate the accessor memory if we haven't done so yet
            if (m_pAccessorInfo == NULL)
            {
                hr = AllocateAccessorMemory(nAccessors);
                if (FAILED(hr))
                    return hr;
            }

            for (ULONG i=0; i<nAccessors && SUCCEEDED(hr); i++)
                hr = BindAccessor(spAccessor, i, nSize);
        }

        return hr;
    }

    HRESULT BindAccessor(IAccessor* pAccessor, ULONG nAccessor, ULONG nSize)
    {
        DBBINDING*  pBindings = NULL;
        ULONG       nColumns;
        bool        bAuto;
        HRESULT     hr;

        // First time just get the number of entries by passing in &nColumns
        _OutputColumnsClass::_GetBindEntries(&nColumns, NULL, nAccessor, NULL);

        // Now allocate the binding structures
        ATLTRY(pBindings = new DBBINDING[nColumns]);
        if (pBindings == NULL)
            return E_OUTOFMEMORY;

        // Now get the bind entries
        hr = _OutputColumnsClass::_GetBindEntries(&nColumns, pBindings, nAccessor, &bAuto);
        if (FAILED(hr))
            return hr;

        m_pAccessorInfo[nAccessor].bAutoAccessor = bAuto;
        hr = BindEntries(pBindings, nColumns, &m_pAccessorInfo[nAccessor].hAccessor, nSize, pAccessor);
        delete [] pBindings;
        return hr;
    }

    HRESULT BindParameters(HACCESSOR* pHAccessor, ICommand* pCommand, void** ppParameterBuffer)
    {
        HRESULT hr = S_OK;
        // In the static accessor case, the parameter buffer will be T
        *ppParameterBuffer = this;

        // Only bind the parameters if we haven't already done it
        if (*pHAccessor == NULL)
        {
            ULONG   nColumns;
            _ParamClass::_GetParamEntries(&nColumns, NULL);

            DBBINDING* pBinding = NULL;
            ATLTRY(pBinding = new DBBINDING[nColumns]);
            if (pBinding == NULL)
                return E_OUTOFMEMORY;

            hr = _ParamClass::_GetParamEntries(&nColumns, pBinding);
            if (SUCCEEDED(hr))
            {
                // Get the IAccessor from the passed IUnknown
                CComPtr<IAccessor> spAccessor;
                hr = pCommand->QueryInterface(&spAccessor);
                if (SUCCEEDED(hr))
                {
                    hr = BindEntries(pBinding, nColumns, pHAccessor, sizeof(T),
                        spAccessor);
                }
            }
            delete [] pBinding;
        }
        return hr;
    }
};


///////////////////////////////////////////////////////////////////////////
// CDynamicAccessor

class CDynamicAccessor :
    public CAccessorBase
{
public:
    CDynamicAccessor()
    {
        m_nColumns        = 0;
        m_pColumnInfo     = NULL;
        m_pStringsBuffer  = NULL;
    };
    ~CDynamicAccessor()
    {
        Close();
    }
    void Close()
    {
        if (m_pColumnInfo != NULL)
        {
            CoTaskMemFree(m_pColumnInfo);
            m_pColumnInfo = NULL;
        }

        // Free the memory for the string buffer returned by IColumnsInfo::GetColumnInfo,
        // if necessary
        if (m_pStringsBuffer != NULL)
        {
            CoTaskMemFree(m_pStringsBuffer);
            m_pStringsBuffer = NULL;
        }

        delete [] m_pBuffer;
        m_pBuffer = NULL;
        m_nColumns = 0;

        CAccessorBase::Close();
    }
    bool GetColumnType(ULONG nColumn, DBTYPE* pType) const
    {
        if (TranslateColumnNo(nColumn))
        {
            *pType = m_pColumnInfo[nColumn].wType;
            return true;
        }
        else
            return false;
    }
    bool GetColumnFlags(ULONG nColumn, DBCOLUMNFLAGS* pFlags) const
    {
        if (TranslateColumnNo(nColumn))
        {
            *pFlags = m_pColumnInfo[nColumn].dwFlags;
            return true;
        }
        else
            return false;
    }
    bool GetOrdinal(TCHAR* pColumnName, ULONG* pOrdinal) const
    {
        ATLASSERT(pColumnName != NULL);
        ULONG nColumn;
        if (GetInternalColumnNo(pColumnName, &nColumn))
        {
            *pOrdinal = m_pColumnInfo[nColumn].iOrdinal;
            return true;
        }
        else
            return false;
    }

    void* GetValue(ULONG nColumn) const
    {
        if (TranslateColumnNo(nColumn))
            return _GetDataPtr(nColumn);
        else
            return NULL;
    }

    void* GetValue(TCHAR* pColumnName) const
    {
        ATLASSERT(pColumnName != NULL);
        ULONG nColumn;
        if (GetInternalColumnNo(pColumnName, &nColumn))
            return _GetDataPtr(nColumn);
        else
            return NULL;    // Not Found
    }

    template <class ctype>
    void _GetValue(ULONG nColumn, ctype* pData) const
    {
        ATLASSERT(pData != NULL);
        ATLASSERT(m_pColumnInfo[nColumn].ulColumnSize == sizeof(ctype));
        ctype* pBuffer = (ctype*)_GetDataPtr(nColumn);
        *pData = *pBuffer;
    }
    template <class ctype>
    void _SetValue(ULONG nColumn, const ctype& data)
    {
        ATLASSERT(m_pColumnInfo[nColumn].ulColumnSize == sizeof(ctype));
        ctype* pBuffer = (ctype*)_GetDataPtr(nColumn);
        *pBuffer = (ctype)data;
    }
    template <class ctype>
    bool GetValue(ULONG nColumn, ctype* pData) const
    {
        if (TranslateColumnNo(nColumn))
        {
            _GetValue(nColumn, pData);
            return true;
        }
        return false;
    }
    template <class ctype>
    bool SetValue(ULONG nColumn, const ctype& data)
    {
        if (TranslateColumnNo(nColumn))
        {
            _SetValue(nColumn, data);
            return true;
        }
        return false;
    }
    template <class ctype>
    bool GetValue(TCHAR *pColumnName, ctype* pData) const
    {
        ATLASSERT(pColumnName != NULL);
        ULONG nColumn;
        if (GetInternalColumnNo(pColumnName, &nColumn))
        {
            _GetValue(nColumn, pData);
            return true;
        }
        return false;
    }
    template <class ctype>
    bool SetValue(TCHAR *pColumnName, const ctype& data)
    {
        ATLASSERT(pColumnName != NULL);
        ULONG nColumn;
        if (GetInternalColumnNo(pColumnName, &nColumn))
        {
            _SetValue(nColumn, data);
            return true;
        }
        return false;
    }
    bool GetLength(ULONG nColumn, ULONG* pLength) const
    {
        ATLASSERT(pLength != NULL);
        if (TranslateColumnNo(nColumn))
        {
            *pLength = *(ULONG*)(AddOffset((ULONG)_GetDataPtr(nColumn), m_pColumnInfo[nColumn].ulColumnSize));
            return true;
        }
        else
            return false;
    }
    bool SetLength(ULONG nColumn, ULONG nLength)
    {
        if (TranslateColumnNo(nColumn))
        {
            *(ULONG*)(AddOffset((ULONG)_GetDataPtr(nColumn), m_pColumnInfo[nColumn].ulColumnSize)) = nLength;
            return true;
        }
        else
            return false;
    }
    bool GetLength(TCHAR* pColumnName, ULONG* pLength) const
    {
        ATLASSERT(pColumnName != NULL);
        ATLASSERT(pLength != NULL);
        ULONG nColumn;
        if (GetInternalColumnNo(pColumnName, &nColumn))
        {
            *pLength = *(ULONG*)(AddOffset((ULONG)_GetDataPtr(nColumn), m_pColumnInfo[nColumn].ulColumnSize));
            return true;
        }
        else
            return false;
    }
    bool SetLength(TCHAR* pColumnName, ULONG nLength)
    {
        ATLASSERT(pColumnName != NULL);
        ULONG nColumn;
        if (GetInternalColumnNo(pColumnName, &nColumn))
        {
            *(ULONG*)(AddOffset((ULONG)_GetDataPtr(nColumn), m_pColumnInfo[nColumn].ulColumnSize)) = nLength;
            return true;
        }
        else
            return false;
    }
    bool GetStatus(ULONG nColumn, DBSTATUS* pStatus) const
    {
        ATLASSERT(pStatus != NULL);
        if (TranslateColumnNo(nColumn))
        {
            *pStatus = *(ULONG*)(AddOffset(AddOffset((ULONG)_GetDataPtr(nColumn), m_pColumnInfo[nColumn].ulColumnSize), sizeof(ULONG)));
            return true;
        }
        else
            return false;
    }
    bool SetStatus(ULONG nColumn, DBSTATUS status)
    {
        if (TranslateColumnNo(nColumn))
        {
            *(ULONG*)(AddOffset(AddOffset((ULONG)_GetDataPtr(nColumn), m_pColumnInfo[nColumn].ulColumnSize), sizeof(ULONG))) = status;
            return true;
        }
        else
            return false;
    }
    bool GetStatus(TCHAR* pColumnName, DBSTATUS* pStatus) const
    {
        ATLASSERT(pColumnName != NULL);
        ATLASSERT(pStatus != NULL);
        ULONG nColumn;
        if (GetInternalColumnNo(pColumnName, &nColumn))
        {
            *pStatus = *(ULONG*)((BYTE*)_GetDataPtr(nColumn) + m_pColumnInfo[nColumn].ulColumnSize + sizeof(ULONG));
            return true;
        }
        else
            return false;
    }
    bool SetStatus(TCHAR* pColumnName, DBSTATUS status)
    {
        ATLASSERT(pColumnName != NULL);
        ULONG nColumn;
        if (GetInternalColumnNo(pColumnName, &nColumn))
        {
            *(ULONG*)((BYTE*)_GetDataPtr(nColumn) + m_pColumnInfo[nColumn].ulColumnSize + sizeof(ULONG)) = status;
            return true;
        }
        else
            return false;
    }

    // Returns true if a bookmark is available
    HRESULT GetBookmark(CBookmark<>* pBookmark) const
    {
        HRESULT hr;
        if (m_pColumnInfo->iOrdinal == 0)
            hr = pBookmark->SetBookmark(m_pColumnInfo->ulColumnSize, (BYTE*)_GetDataPtr(0));
        else
            hr = E_FAIL;
        return hr;
    }

    ULONG GetColumnCount() const
    {
        return m_nColumns;
    }

    LPOLESTR GetColumnName(ULONG nColumn) const
    {
        if (TranslateColumnNo(nColumn))
            return m_pColumnInfo[nColumn].pwszName;
        else
            return NULL;
    }

    HRESULT GetColumnInfo(IRowset* pRowset, ULONG* pColumns, DBCOLUMNINFO** ppColumnInfo)
    {
        CComPtr<IColumnsInfo> spColumnsInfo;
        HRESULT hr = pRowset->QueryInterface(&spColumnsInfo);
        if (SUCCEEDED(hr))
            hr = spColumnsInfo->GetColumnInfo(pColumns, ppColumnInfo, &m_pStringsBuffer);

        return hr;
    }

    HRESULT AddBindEntry(const DBCOLUMNINFO& info)
    {
        m_pColumnInfo = (DBCOLUMNINFO*)CoTaskMemRealloc(m_pColumnInfo, (m_nColumns + 1) * sizeof(DBCOLUMNINFO));
        if (m_pColumnInfo == NULL)
            return E_OUTOFMEMORY;

        m_pColumnInfo[m_nColumns] = info;
        m_nColumns++;

        return S_OK;
    }

// Implementation
    // Free's any columns in the current record that need to be freed.
    // E.g. Calls SysFreeString on any BSTR's and Release on any interfaces.
    void FreeRecordMemory(IRowset* pRowset)
    {
        ULONG i;

        for (i = 0; i < m_nColumns; i++)
            CAccessorBase::FreeType(m_pColumnInfo[i].wType, (BYTE*)_GetDataPtr(i), pRowset);
    }
    void* _GetDataPtr(ULONG nColumn) const
    {
        return m_pBuffer + (ULONG)m_pColumnInfo[nColumn].pTypeInfo;
    }
    bool GetInternalColumnNo(TCHAR* pColumnName, ULONG* pColumn) const
    {
        ATLASSERT(pColumnName != NULL);
        ATLASSERT(pColumn != NULL);
        USES_CONVERSION;
        ULONG       i;
        ULONG       nSize = (lstrlen(pColumnName) + 1) * sizeof(OLECHAR);
        OLECHAR*    pOleColumnName = T2OLE(pColumnName);

        // Search through the columns trying to find a match
        for (i = 0; i < m_nColumns; i++)
        {
            if (m_pColumnInfo[i].pwszName != NULL &&
                memcmp(m_pColumnInfo[i].pwszName, pOleColumnName, nSize) == 0)
                break;
        }
        if (i < m_nColumns)
        {
            *pColumn = i;
            return true;
        }
        else
            return false;   // Not Found
    }
    HRESULT BindColumns(IUnknown* pUnk)
    {
        ATLASSERT(pUnk != NULL);
        CComPtr<IAccessor> spAccessor;
        HRESULT hr = pUnk->QueryInterface(&spAccessor);
        if (FAILED(hr))
            return hr;

        ULONG   i;
        ULONG   nOffset = 0, nLengthOffset, nStatusOffset;

        // If the user hasn't specifed the column information to bind by calling AddBindEntry then
        // we get it ourselves
        if (m_pColumnInfo == NULL)
        {
            CComPtr<IColumnsInfo> spColumnsInfo;
            hr = pUnk->QueryInterface(&spColumnsInfo);
            if (FAILED(hr))
                return hr;

            hr = spColumnsInfo->GetColumnInfo(&m_nColumns, &m_pColumnInfo, &m_pStringsBuffer);
            if (FAILED(hr))
                return hr;

            m_bOverride = false;
        }
        else
            m_bOverride = true;

        DBBINDING* pBinding = NULL;
        ATLTRY(pBinding= new DBBINDING[m_nColumns]);
        if (pBinding == NULL)
            return E_OUTOFMEMORY;

        DBBINDING* pCurrent = pBinding;
        DBOBJECT*  pObject;
        for (i = 0; i < m_nColumns; i++)
        {
            // If it's a BLOB or the column size is large enough for us to treat it as
            // a BLOB then we also need to set up the DBOBJECT structure.
            if (m_pColumnInfo[i].ulColumnSize > 1024 || m_pColumnInfo[i].wType == DBTYPE_IUNKNOWN)
            {
                pObject = NULL;
                ATLTRY(pObject = new DBOBJECT);
                if (pObject == NULL)
                    return E_OUTOFMEMORY;
                pObject->dwFlags = STGM_READ;
                pObject->iid     = IID_ISequentialStream;
                m_pColumnInfo[i].wType      = DBTYPE_IUNKNOWN;
                m_pColumnInfo[i].ulColumnSize   = sizeof(IUnknown*);
            }
            else
                pObject = NULL;

            // If column is of type STR or WSTR increase length by 1
            // to accommodate the NULL terminator.
            if (m_pColumnInfo[i].wType == DBTYPE_STR ||
                m_pColumnInfo[i].wType == DBTYPE_WSTR)
                    m_pColumnInfo[i].ulColumnSize += 1;

            nLengthOffset = AddOffset(nOffset, m_pColumnInfo[i].ulColumnSize);
            nStatusOffset = AddOffset(nLengthOffset, sizeof(ULONG));
            Bind(pCurrent, m_pColumnInfo[i].iOrdinal, m_pColumnInfo[i].wType,
                m_pColumnInfo[i].ulColumnSize, m_pColumnInfo[i].bPrecision, m_pColumnInfo[i].bScale,
                DBPARAMIO_NOTPARAM, nOffset,
                nLengthOffset, nStatusOffset, pObject);
            pCurrent++;

            // Note that, as we're not using this for anything else, we're using the
            // pTypeInfo element to store the offset to our data.
            m_pColumnInfo[i].pTypeInfo = (ITypeInfo*)nOffset;

            nOffset = AddOffset(nStatusOffset, sizeof(DBSTATUS));
        }
        // Allocate the accessor memory if we haven't done so yet
        if (m_pAccessorInfo == NULL)
        {
            hr = AllocateAccessorMemory(1); // We only have one accessor
            if (FAILED(hr))
            {
                delete [] pBinding;
                return hr;
            }
            m_pAccessorInfo->bAutoAccessor = TRUE;
        }

        // Allocate enough memory for the data buffer and tell the rowset
        // Note that the rowset will free the memory in its destructor.
        m_pBuffer = NULL;
        ATLTRY(m_pBuffer = new BYTE[nOffset]);
        if (m_pBuffer == NULL)
        {
            delete [] pBinding;
            return E_OUTOFMEMORY;
        }
        hr = BindEntries(pBinding, m_nColumns, &m_pAccessorInfo->hAccessor,
                nOffset, spAccessor);
        delete [] pBinding;

        return hr;
    }

    static ULONG AddOffset(ULONG nCurrent, ULONG nAdd)
    {
        struct foobar
        {
            char    foo;
            long    bar;
        };
        ULONG nAlign = offsetof(foobar, bar);

        return nCurrent + nAdd + (nAdd % nAlign);;
    }

    // Translate the column number to the index into the column info array
    bool TranslateColumnNo(ULONG& nColumn) const
    {
        ATLASSERT(m_pColumnInfo != NULL);
        // If the user has overriden the binding then we need to search
        // through the column info for the ordinal number
        if (m_bOverride)
        {
            for (ULONG i = 0; i < m_nColumns; i++)
            {
                if (m_pColumnInfo[i].iOrdinal == nColumn)
                {
                    nColumn = i;
                    return true;
                }
            }
            return false;
        }
        else
        {
            // Note that m_pColumnInfo->iOrdinal will be zero if have bound
            // a bookmark as the first entry, otherwise it will be 1.
            // If the column is out of range then return false
            if (nColumn > (m_nColumns - 1 + m_pColumnInfo->iOrdinal))
                return false;

            // otherwise translate the column to an index into our internal
            // binding entries array
            nColumn -= m_pColumnInfo->iOrdinal;
            return true;
        }
    }
    typedef CDynamicAccessor _OutputColumnsClass;
    static bool HasOutputColumns() { return true; }

    ULONG               m_nColumns;
    DBCOLUMNINFO*       m_pColumnInfo;
    OLECHAR*            m_pStringsBuffer;
    bool                m_bOverride;
};


///////////////////////////////////////////////////////////////////////////
// class CDynamicParameterAccessor

class CDynamicParameterAccessor : public CDynamicAccessor
{
// Constructors and Destructors
public:
    typedef CDynamicParameterAccessor _ParamClass;
    CDynamicParameterAccessor()
    {
        m_pParameterEntry       = NULL;
        m_pParameterBuffer      = NULL;
        m_ppParamName           = NULL;
        m_nParameterBufferSize  = 0;
        m_nParams               = 0;
    };

    ~CDynamicParameterAccessor()
    {
        delete [] m_pParameterEntry;
        if (m_ppParamName != NULL)
        {
            if (*m_ppParamName != NULL)
                CoTaskMemFree(*m_ppParamName);
            delete [] m_ppParamName;
        }
        delete m_pParameterBuffer;
    };
    // nParam is the parameter number (offset from 1)
    bool GetParamType(ULONG nParam, DBTYPE* pType) const
    {
        ATLASSERT(pType != NULL);
        if (nParam == 0 || nParam > m_nParams)
            return false;

        *pType = m_pParameterEntry[nParam-1].wType;
        return true;
    }
    template <class ctype>
    bool GetParam(ULONG nParam, ctype* pData) const
    {
        ATLASSERT(pData != NULL);
        ctype* pBuffer = (ctype*)GetParam(nParam);
        if (pBuffer == NULL)
            return false;
        *pData = *pBuffer;
        return true;

    }
    template <class ctype>
    bool SetParam(ULONG nParam, ctype* pData)
    {
        ATLASSERT(pData != NULL);
        ctype* pBuffer = (ctype*)GetParam(nParam);
        if (pBuffer == NULL)
            return false;
        *pBuffer = *pData;
        return true;

    }
    template <class ctype>
    bool GetParam(TCHAR* pParamName, ctype* pData) const
    {
        ATLASSERT(pData != NULL);
        ctype* pBuffer = (ctype*)GetParam(pParamName);
        if (pBuffer == NULL)
            return false;
        *pData = *pBuffer;
        return true;

    }
    template <class ctype>
    bool SetParam(TCHAR* pParamName, ctype* pData)
    {
        ATLASSERT(pData != NULL);
        ctype* pBuffer = (ctype*)GetParam(pParamName);
        if (pBuffer == NULL)
            return false;
        *pBuffer = *pData;
        return true;

    }
    void* GetParam(ULONG nParam) const
    {
        if (nParam == 0 || nParam > m_nParams)
            return NULL;
        else
            return m_pParameterBuffer + m_pParameterEntry[nParam-1].obValue;
    }
    void* GetParam(TCHAR* pParamName) const
    {
        USES_CONVERSION;
        ULONG    i;
        ULONG       nSize = (lstrlen(pParamName) + 1) * sizeof(OLECHAR);
        OLECHAR*    pOleParamName = T2OLE(pParamName);

        for (i=0; i<m_nParams; i++)
        {
            if (memcmp(m_ppParamName[i], pOleParamName, nSize) == 0)
                break;
        }
        if (i < m_nParams)
            return (m_pParameterBuffer + m_pParameterEntry[i].obValue);
        else
            return NULL;    // Not Found
    }
    // Get the number of parameters
    ULONG GetParamCount() const
    {
        return m_nParams;
    }
    // Get the parameter name for the passed parameter number
    LPOLESTR GetParamName(ULONG ulParam) const
    {
        ATLASSERT((ulParam >= 0) && (ulParam<m_nParams));
        return m_ppParamName[ulParam];
    }

// Implementation
    HRESULT BindParameters(HACCESSOR* pHAccessor, ICommand* pCommand,
                void** ppParameterBuffer)
    {
        // If we have already bound the parameters then just return
        // the pointer to the parameter buffer
        if (*pHAccessor != NULL)
        {
            *ppParameterBuffer = m_pParameterBuffer;
            return S_OK;
        }

        CComPtr<IAccessor> spAccessor;
        HRESULT hr = pCommand->QueryInterface(&spAccessor);
        if (FAILED(hr))
            return hr;

        // Try to bind parameters if available
        CComPtr<ICommandWithParameters> spCommandParameters;
        hr = pCommand->QueryInterface(&spCommandParameters);
        if (FAILED(hr))
            return hr;

        ULONG           ulParams     = 0;
        DBPARAMINFO*    pParamInfo   = NULL;
        LPOLESTR        pNamesBuffer = NULL;

        // Get Parameter Information
        hr = spCommandParameters->GetParameterInfo(&ulParams, &pParamInfo,
                &pNamesBuffer);
        if (FAILED(hr))
            return hr;

        // Create the parameter information for binding
        hr = AllocateParameterInfo(ulParams);
        if (FAILED(hr))
        {
            CoTaskMemFree(pParamInfo);
            CoTaskMemFree(pNamesBuffer);
            return hr;
        }

        ULONG nOffset = 0;
        DBBINDING* pCurrent = m_pParameterEntry;
        for (ULONG l=0; l<ulParams; l++)
        {
            m_pParameterEntry[l].eParamIO = 0;
            if (pParamInfo[l].dwFlags & DBPARAMFLAGS_ISINPUT)
                m_pParameterEntry[l].eParamIO |= DBPARAMIO_INPUT;

            if (pParamInfo[l].dwFlags & DBPARAMFLAGS_ISOUTPUT)
                m_pParameterEntry[l].eParamIO |= DBPARAMIO_OUTPUT;

            Bind(pCurrent, pParamInfo[l].iOrdinal, pParamInfo[l].wType,
                pParamInfo[l].ulParamSize, pParamInfo[l].bPrecision, pParamInfo[l].bScale,
                m_pParameterEntry[l].eParamIO, nOffset);
            pCurrent++;

            m_ppParamName[l] = pNamesBuffer;
            if (pNamesBuffer && *pNamesBuffer)
            {
                // Search for the NULL termination character
                while (*pNamesBuffer++)
                    ;
            }
            nOffset += pParamInfo[l].ulParamSize;

        }

        // Allocate memory for the new buffer
        m_pParameterBuffer = NULL;
        ATLTRY(m_pParameterBuffer = new BYTE[nOffset]);
        if (m_pParameterBuffer == NULL)
        {
            // Note that pNamesBuffer will be freed in the destructor
            // by freeing *m_ppParamName
            CoTaskMemFree(pParamInfo);
            return E_OUTOFMEMORY;
        }
        *ppParameterBuffer = m_pParameterBuffer;
        m_nParameterBufferSize = nOffset;
        m_nParams = ulParams;
        BindEntries(m_pParameterEntry, ulParams, pHAccessor, nOffset, spAccessor);

        CoTaskMemFree(pParamInfo);

        return S_OK;
    }
    bool HasParameters() const
    {
        return true;
    }
    HRESULT AllocateParameterInfo(int nParamEntries)
    {
        // Allocate memory for the bind structures
        m_pParameterEntry = NULL;
        ATLTRY(m_pParameterEntry = new DBBINDING[nParamEntries]);
        if (m_pParameterEntry == NULL)
            return E_OUTOFMEMORY;

        // Allocate memory to store the field names
        m_ppParamName = NULL;
        ATLTRY(m_ppParamName = new OLECHAR*[nParamEntries]);
        if (m_ppParamName == NULL)
            return E_OUTOFMEMORY;
        return S_OK;
    }

// Data Members
    // Number of parameters
    ULONG               m_nParams;
    // A pointer to the entry structures for each parameter
    DBBINDING*          m_pParameterEntry;
    // String names for the parameters
    OLECHAR**           m_ppParamName;
    // The size of the buffer where the parameters are stored
    ULONG               m_nParameterBufferSize;
    // A pointer to the buffer where the parameters are stored
    BYTE*               m_pParameterBuffer;
};


///////////////////////////////////////////////////////////////////////////
// class CManualAccessor

class CManualAccessor :
    public CAccessorBase
{
public:
    CManualAccessor()
    {
        // By default we don't have any parameters unless CreateParameterAccessor is called
        m_pEntry          = NULL;
        m_nParameters     = 0;
        m_pParameterEntry = NULL;
        m_nColumns        = 0;
    }
    ~CManualAccessor()
    {
        delete [] m_pEntry;
        delete [] m_pParameterEntry;
    }
    HRESULT CreateAccessor(int nBindEntries, void* pBuffer, ULONG nBufferSize)
    {
        m_pBuffer     = (BYTE*)pBuffer;
        m_nBufferSize = nBufferSize;
        m_nColumns    = nBindEntries;
        m_nEntry      = 0;

        // If they've previously created some entries then free them
        delete [] m_pEntry;
        m_pEntry = NULL;

        // Allocate memory for the bind structures
        ATLTRY(m_pEntry = new DBBINDING[nBindEntries]);
        if (m_pEntry == NULL)
            return E_OUTOFMEMORY;
        else
            return S_OK;
    }
    HRESULT CreateParameterAccessor(int nBindEntries, void* pBuffer, ULONG nBufferSize)
    {
        m_pParameterBuffer     = (BYTE*)pBuffer;
        m_nParameterBufferSize = nBufferSize;
        m_nParameters          = nBindEntries;
        m_nCurrentParameter    = 0;

        // Allocate memory for the bind structures
        m_pParameterEntry = NULL;
        ATLTRY(m_pParameterEntry  = new DBBINDING[nBindEntries]);
        if (m_pParameterEntry == NULL)
            return E_OUTOFMEMORY;
        else
            return S_OK;
    }
    void AddBindEntry(ULONG nOrdinal, DBTYPE wType, ULONG nColumnSize,
            void* pData, void* pLength = NULL, void* pStatus = NULL)
    {
        ATLASSERT(m_nEntry < m_nColumns);
        ULONG   nLengthOffset, nStatusOffset;

        if (pStatus != NULL)
            nStatusOffset = (BYTE*)pStatus - m_pBuffer;
        else
            nStatusOffset = 0;

        if (pLength != NULL)
            nLengthOffset = (BYTE*)pLength - m_pBuffer;
        else
            nLengthOffset = 0;

        Bind(m_pEntry+m_nEntry, nOrdinal, wType, nColumnSize, 0, 0, DBPARAMIO_NOTPARAM,
            (BYTE*)pData - m_pBuffer, nLengthOffset, nStatusOffset);

        m_nEntry++;
    }
    void AddParameterEntry(ULONG nOrdinal, DBTYPE wType, ULONG nColumnSize,
            void* pData, void* pLength = NULL, void* pStatus = NULL,
            DBPARAMIO eParamIO = DBPARAMIO_INPUT)
    {
        ATLASSERT(m_nCurrentParameter < m_nParameters);
        ULONG   nLengthOffset, nStatusOffset;

        if (pStatus != NULL)
            nStatusOffset = (BYTE*)pStatus - m_pParameterBuffer;
        else
            nStatusOffset = 0;

        if (pLength != NULL)
            nLengthOffset = (BYTE*)pLength - m_pBuffer;
        else
            nLengthOffset = 0;

        Bind(m_pParameterEntry + m_nCurrentParameter, nOrdinal, wType, nColumnSize, 0, 0,
            eParamIO, (BYTE*)pData - m_pParameterBuffer, nLengthOffset, nStatusOffset);

        m_nCurrentParameter++;
    }

// Implementation
    // Free's any columns in the current record that need to be freed.
    // E.g. Calls SysFreeString on any BSTR's and Release on any interfaces.
    void FreeRecordMemory(IRowset* pRowset)
    {
        ULONG i;

        for (i = 0; i < m_nColumns; i++)
            CAccessorBase::FreeType(m_pEntry[i].wType, m_pBuffer + m_pEntry[i].obValue, pRowset);
    }
    HRESULT BindColumns(IUnknown* pUnk)
    {
        ATLASSERT(pUnk != NULL);
        CComPtr<IAccessor> spAccessor;
        HRESULT hr = pUnk->QueryInterface(&spAccessor);
        if (FAILED(hr))
            return hr;

        // Allocate the accessor memory if we haven't done so yet
        if (m_pAccessorInfo == NULL)
        {
            hr = AllocateAccessorMemory(1); // We only have one accessor
            if (FAILED(hr))
                return hr;
            m_pAccessorInfo->bAutoAccessor = TRUE;
        }

        return BindEntries(m_pEntry, m_nColumns, &m_pAccessorInfo->hAccessor, m_nBufferSize, spAccessor);
    }

    HRESULT BindParameters(HACCESSOR* pHAccessor, ICommand* pCommand, void** ppParameterBuffer)
    {
        HRESULT hr;
        *ppParameterBuffer = m_pParameterBuffer;

        // Only bind the parameter if we haven't done so yet
        if (*pHAccessor == NULL)
        {
            // Get the IAccessor from the passed IUnknown
            CComPtr<IAccessor> spAccessor;
            hr = pCommand->QueryInterface(&spAccessor);
            if (SUCCEEDED(hr))
            {
                hr = BindEntries(m_pParameterEntry, m_nParameters, pHAccessor,
                        m_nParameterBufferSize, spAccessor);
            }
        }
        else
            hr = S_OK;

        return hr;
    }
    typedef CManualAccessor _ParamClass;
    bool HasParameters() { return (m_nParameters > 0); }
    typedef CManualAccessor _OutputColumnsClass;
    static bool HasOutputColumns() { return true; }
    ULONG GetColumnCount() const
    {
        return m_nColumns;
    }

    // The binding structure for the output columns
    DBBINDING*          m_pEntry;
    // The number of output columns
    ULONG               m_nColumns;
    // The number of the current entry for the output columns
    ULONG               m_nEntry;
    // The size of the data buffer for the output columns
    ULONG               m_nBufferSize;
    // The number of parameters columns
    ULONG               m_nParameters;
    // The number of the parameter column to bind next
    ULONG               m_nCurrentParameter;
    // A pointer to the entry structures for each parameter
    DBBINDING*          m_pParameterEntry;
    // The size of the buffer where the parameters are stored
    ULONG               m_nParameterBufferSize;
    // A pointer to the buffer where the parameters are stored
    BYTE*               m_pParameterBuffer;
};


///////////////////////////////////////////////////////////////////////////
// CAccessorRowset

template <class TAccessor = CNoAccessor, class TRowset = CRowset>
class CAccessorRowset :
    public TAccessor,
    public TRowset
{
public:
    CAccessorRowset()
    {
        // Give the rowset a pointer to the accessor
        SetAccessor(this);
    }
    ~CAccessorRowset()
    {
        Close();
    }
    // Used to get the column information from the opened rowset. The user is responsible
    // for freeing the returned column information and string buffer.
    HRESULT GetColumnInfo(ULONG* pulColumns,
        DBCOLUMNINFO** ppColumnInfo, LPOLESTR* ppStrings) const
    {
        ATLASSERT(GetInterface() != NULL);
        if (ppColumnInfo == NULL || pulColumns == NULL || ppStrings == NULL)
            return E_POINTER;

        CComPtr<IColumnsInfo> spColumns;
        HRESULT hr = GetInterface()->QueryInterface(&spColumns);
        if (SUCCEEDED(hr))
            hr = spColumns->GetColumnInfo(pulColumns, ppColumnInfo, ppStrings);

        return hr;
    }
    // Used to get the column information when overriding the bindings using CDynamicAccessor
    // The user should CoTaskMemFree the column information pointer that is returned.
    HRESULT GetColumnInfo(ULONG* pColumns, DBCOLUMNINFO** ppColumnInfo)
    {
        // If you get a compilation here, then you are most likely calling this function
        // from a class that is not using CDynamicAccessor.
        ATLASSERT(GetInterface() != NULL);
        return TAccessor::GetColumnInfo(GetInterface(), pColumns, ppColumnInfo);
    }
    // Call to bind the output columns
    HRESULT Bind()
    {
        // Bind should only be called when we've successfully opened the rowset
        ATLASSERT(GetInterface() != NULL);
        HRESULT hr = TAccessor::BindColumns(GetInterface());
        if (SUCCEEDED(hr))
            hr = BindFinished();
        return hr;
    }
    // Close the opened rowset and release the created accessors for the output columns
    void Close()
    {
        if (GetInterface() != NULL)
        {
            ReleaseAccessors(GetInterface());
            TAccessor::Close();
            TRowset::Close();
        }
    }
    // Free's any columns in the current record that need to be freed.
    // E.g. Calls SysFreeString on any BSTR's and Release on any interfaces.
    void FreeRecordMemory()
    {
        TAccessor::FreeRecordMemory(m_spRowset);
    }
};


///////////////////////////////////////////////////////////////////////////
// class CEnumeratorAccessor

class CEnumeratorAccessor
{
public:
    WCHAR           m_szName[129];
    WCHAR           m_szParseName[129];
    WCHAR           m_szDescription[129];
    USHORT          m_nType;
    VARIANT_BOOL    m_bIsParent;

// Binding Maps
BEGIN_COLUMN_MAP(CEnumeratorAccessor)
    COLUMN_ENTRY(1, m_szName)
    COLUMN_ENTRY(2, m_szParseName)
    COLUMN_ENTRY(3, m_szDescription)
    COLUMN_ENTRY(4, m_nType)
    COLUMN_ENTRY(5, m_bIsParent)
END_COLUMN_MAP()
};


///////////////////////////////////////////////////////////////////////////
// class CEnumerator

class CEnumerator : public CAccessorRowset<CAccessor<CEnumeratorAccessor> >
{
public:
    HRESULT Open(LPMONIKER pMoniker)
    {
        if (pMoniker == NULL)
            return E_FAIL;

        // Bind the moniker for the sources rowset
        if (FAILED(BindMoniker(pMoniker, 0, IID_ISourcesRowset,
                    (void**)&m_spSourcesRowset)))
            return E_FAIL;

        // Enumerate the data sources
        if (FAILED(m_spSourcesRowset->GetSourcesRowset(NULL, IID_IRowset, 0,
            NULL, (IUnknown**)&m_spRowset)))
            return E_FAIL;

        return Bind();
    }
    HRESULT Open(const CEnumerator& enumerator)
    {
        HRESULT hr;
        CComPtr<IMoniker> spMoniker;

        hr = enumerator.GetMoniker(&spMoniker);
        if (FAILED(hr))
            return hr;

        return Open(spMoniker);
    }
    HRESULT Open(const CLSID* pClsid = &CLSID_OLEDB_ENUMERATOR)
    {
        if (pClsid == NULL)
            return E_FAIL;

        HRESULT hr;
        // Create the enumerator
        hr = CoCreateInstance(*pClsid, NULL, CLSCTX_INPROC_SERVER,
                IID_ISourcesRowset, (LPVOID*)&m_spSourcesRowset);
        if (FAILED(hr))
            return hr;

        // Get the rowset so we can enumerate the data sources
        hr = m_spSourcesRowset->GetSourcesRowset(NULL, IID_IRowset, 0,
            NULL, (IUnknown**)&m_spRowset);
        if (FAILED(hr))
            return hr;

        return Bind();
    }

    HRESULT GetMoniker(LPMONIKER* ppMoniker) const
    {
        CComPtr<IParseDisplayName> spParse;
        HRESULT hr;
        ULONG   chEaten;

        if (ppMoniker == NULL)
            return E_POINTER;

        if (m_spSourcesRowset == NULL)
            return E_FAIL;

        hr = m_spSourcesRowset->QueryInterface(IID_IParseDisplayName, (void**)&spParse);
        if (FAILED(hr))
            return hr;

        hr = spParse->ParseDisplayName(NULL, (LPOLESTR)m_szParseName,
                &chEaten, ppMoniker);
        return hr;
    }

    HRESULT GetMoniker(LPMONIKER* ppMoniker, LPCTSTR lpszDisplayName) const
    {
        USES_CONVERSION;
        CComPtr<IParseDisplayName> spParse;
        HRESULT hr;
        ULONG   chEaten;

        if (ppMoniker == NULL || lpszDisplayName == NULL)
            return E_POINTER;

        if (m_spSourcesRowset == NULL)
            return E_FAIL;

        hr = m_spSourcesRowset->QueryInterface(IID_IParseDisplayName, (void**)&spParse);
        if (FAILED(hr))
            return hr;

        hr = spParse->ParseDisplayName(NULL, (LPOLESTR)T2COLE(lpszDisplayName),
                &chEaten, ppMoniker);
        return hr;
    }

    bool Find(TCHAR* szSearchName)
    {
        USES_CONVERSION;
        // Loop through the providers looking for the passed name
        while (MoveNext()==S_OK && lstrcmp(W2T(m_szName), szSearchName))
            ATLTRACE2(atlTraceDBClient, 0, _T("%s, %s, %d\n"), W2T(m_szName), W2T(m_szParseName), m_nType);
        if (lstrcmp(W2T(m_szName), szSearchName))
            return false;
        else
            return true;
    }

    CComPtr<ISourcesRowset> m_spSourcesRowset;
};


///////////////////////////////////////////////////////////////////////////
// CDataSource

class CDataSource
{
public:
    HRESULT Open(const CLSID& clsid, DBPROPSET* pPropSet = NULL, ULONG nPropertySets=1)
    {
        HRESULT hr;

        m_spInit.Release();
        hr = CoCreateInstance(clsid, NULL, CLSCTX_INPROC_SERVER, IID_IDBInitialize,
                (void**)&m_spInit);
        if (FAILED(hr))
            return hr;

        // Initialize the provider
        return OpenWithProperties(pPropSet, nPropertySets);
    }
    HRESULT Open(const CLSID& clsid, LPCTSTR pName, LPCTSTR pUserName = NULL,
        LPCTSTR pPassword = NULL, long nInitMode = 0)
    {
        HRESULT   hr;

        m_spInit.Release();
        hr = CoCreateInstance(clsid, NULL, CLSCTX_INPROC_SERVER, IID_IDBInitialize,
                (void**)&m_spInit);
        if (FAILED(hr))
            return hr;

        return OpenWithNameUserPassword(pName, pUserName, pPassword, nInitMode);
    }
    HRESULT Open(LPCTSTR szProgID, DBPROPSET* pPropSet = NULL, ULONG nPropertySets=1)
    {
        USES_CONVERSION;
        HRESULT hr;
        CLSID   clsid;

        hr = CLSIDFromProgID(T2COLE(szProgID), &clsid);
        if (FAILED(hr))
            return hr;

        return Open(clsid, pPropSet, nPropertySets);
    }
    HRESULT Open(LPCTSTR szProgID, LPCTSTR pName, LPCTSTR pUserName = NULL,
        LPCTSTR pPassword = NULL, long nInitMode = 0)
    {
        USES_CONVERSION;
        HRESULT hr;
        CLSID   clsid;

        hr = CLSIDFromProgID(T2COLE(szProgID), &clsid);
        if (FAILED(hr))
            return hr;

        return Open(clsid, pName, pUserName, pPassword, nInitMode);
    }
    HRESULT Open(const CEnumerator& enumerator, DBPROPSET* pPropSet = NULL, ULONG nPropertySets=1)
    {
        CComPtr<IMoniker> spMoniker;
        HRESULT   hr;

        hr = enumerator.GetMoniker(&spMoniker);
        if (FAILED(hr))
            return hr;

        m_spInit.Release();
        //  Now bind the moniker
        hr = BindMoniker(spMoniker, 0, IID_IDBInitialize, (void**)&m_spInit);
        if (FAILED(hr))
            return hr;

        return OpenWithProperties(pPropSet, nPropertySets);
    }
    HRESULT Open(const CEnumerator& enumerator, LPCTSTR pName, LPCTSTR pUserName = NULL,
        LPCTSTR pPassword = NULL, long nInitMode = 0)
    {
        CComPtr<IMoniker> spMoniker;
        HRESULT   hr;

        hr = enumerator.GetMoniker(&spMoniker);
        if (FAILED(hr))
            return hr;

        m_spInit.Release();
        //  Now bind the moniker
        hr = BindMoniker(spMoniker, 0, IID_IDBInitialize, (void**)&m_spInit);
        if (FAILED(hr))
            return hr;

        return OpenWithNameUserPassword(pName, pUserName, pPassword, nInitMode);
    }
    // Invoke the data links dialog and open the selected database
    HRESULT Open(HWND hWnd = GetActiveWindow(), DBPROMPTOPTIONS dwPromptOptions = DBPROMPTOPTIONS_WIZARDSHEET)
    {
        CComPtr<IDBPromptInitialize> spDBInit;

        HRESULT hr = CoCreateInstance(CLSID_DataLinks, NULL, CLSCTX_INPROC_SERVER,
            IID_IDBPromptInitialize, (void**) &spDBInit);
        if (FAILED(hr))
            return hr;

        CComPtr<IDBProperties> spIDBProperties;
        hr = spDBInit->PromptDataSource(NULL, hWnd, dwPromptOptions, 0, NULL, NULL,
            IID_IDBProperties, (IUnknown**)&spIDBProperties);

        if (hr == S_OK)
        {
            hr = spIDBProperties->QueryInterface(&m_spInit);
            if (SUCCEEDED(hr))
                hr = m_spInit->Initialize();
        }
        else if (hr == S_FALSE)
            hr = MAKE_HRESULT(SEVERITY_ERROR, FACILITY_WIN32, ERROR_CANCELLED);  // The user clicked cancel

        return hr;
    }
    // Opens a data source using the service components
    HRESULT OpenWithServiceComponents(const CLSID& clsid, DBPROPSET* pPropSet = NULL, ULONG nPropertySets=1)
    {
        CComPtr<IDataInitialize> spDataInit;
        HRESULT hr;

        hr = CoCreateInstance(CLSID_MSDAINITIALIZE, NULL, CLSCTX_INPROC_SERVER,
            IID_IDataInitialize, (void**)&spDataInit);
        if (FAILED(hr))
            return hr;

        m_spInit.Release();
        hr = spDataInit->CreateDBInstance(clsid, NULL, CLSCTX_INPROC_SERVER, NULL,
            IID_IDBInitialize, (IUnknown**)&m_spInit);
        if (FAILED(hr))
            return hr;

        // Initialize the provider
        return OpenWithProperties(pPropSet, nPropertySets);
    }
    // Opens a data source using the service components
    HRESULT OpenWithServiceComponents(LPCTSTR szProgID, DBPROPSET* pPropSet = NULL, ULONG nPropertySets=1)
    {
        USES_CONVERSION;
        HRESULT hr;
        CLSID   clsid;

        hr = CLSIDFromProgID(T2COLE(szProgID), &clsid);
        if (FAILED(hr))
            return hr;

        return OpenWithServiceComponents(clsid, pPropSet, nPropertySets);
    }
    // Bring up the "Organize Dialog" which allows the user to select a previously created data link
    // file (.UDL file). The selected file will be used to open the datbase.
    HRESULT OpenWithPromptFileName(HWND hWnd = GetActiveWindow(), DBPROMPTOPTIONS dwPromptOptions = DBPROMPTOPTIONS_NONE,
        LPCOLESTR szInitialDirectory = NULL)
    {
        USES_CONVERSION;
        CComPtr<IDBPromptInitialize> spDBInit;

        HRESULT hr = CoCreateInstance(CLSID_DataLinks, NULL, CLSCTX_INPROC_SERVER,
            IID_IDBPromptInitialize, (void**) &spDBInit);
        if (FAILED(hr))
            return hr;

        CComPtr<IDBProperties> spIDBProperties;
        LPOLESTR szSelected;

        hr = spDBInit->PromptFileName(hWnd, dwPromptOptions, szInitialDirectory, L"*.udl", &szSelected);

        if (hr == S_OK)
            hr = OpenFromFileName(szSelected);
        else if (hr == S_FALSE)
            hr = MAKE_HRESULT(SEVERITY_ERROR, FACILITY_WIN32, ERROR_CANCELLED);  // The user clicked cancel

        return hr;
    }
    // Open the datasource specified by the passed filename, typically a .UDL file
    HRESULT OpenFromFileName(LPCOLESTR szFileName)
    {
        CComPtr<IDataInitialize> spDataInit;
        LPOLESTR                 szInitString;

        HRESULT hr = CoCreateInstance(CLSID_MSDAINITIALIZE, NULL, CLSCTX_INPROC_SERVER,
            IID_IDataInitialize, (void**)&spDataInit);
        if (FAILED(hr))
            return hr;

        hr = spDataInit->LoadStringFromStorage(szFileName, &szInitString);
        if (FAILED(hr))
            return hr;

        return OpenFromInitializationString(szInitString);
    }
    // Open the datasource specified by the passed initialization string
    HRESULT OpenFromInitializationString(LPCOLESTR szInitializationString)
    {
        CComPtr<IDataInitialize> spDataInit;

        HRESULT hr = CoCreateInstance(CLSID_MSDAINITIALIZE, NULL, CLSCTX_INPROC_SERVER,
            IID_IDataInitialize, (void**)&spDataInit);
        if (FAILED(hr))
            return hr;

        CComPtr<IDBProperties> spIDBProperties;
        hr = spDataInit->GetDataSource(NULL, CLSCTX_INPROC_SERVER, szInitializationString,
            IID_IDBInitialize, (IUnknown**)&m_spInit);
        if (FAILED(hr))
            return hr;

        return m_spInit->Initialize();
    }
    // Get the initialization string from the currently open data source. The returned string
    // must be CoTaskMemFree'd when finished with.
    HRESULT GetInitializationString(BSTR* pInitializationString, bool bIncludePassword=false)
    {
        // If the datasource isn't open then we're not going to get an init string
        _ASSERTE(m_spInit != NULL);
        CComPtr<IDataInitialize> spDataInit;
        LPOLESTR    szInitString;

        HRESULT hr = CoCreateInstance(CLSID_MSDAINITIALIZE, NULL, CLSCTX_INPROC_SERVER,
            IID_IDataInitialize, (void**)&spDataInit);
        if (FAILED(hr))
            return hr;

        hr = spDataInit->GetInitializationString(m_spInit, bIncludePassword, &szInitString);

        if (SUCCEEDED(hr))
            *pInitializationString = ::SysAllocString(szInitString);

        return hr;
    }
    HRESULT GetProperties(ULONG ulPropIDSets, const DBPROPIDSET* pPropIDSet,
                ULONG* pulPropertySets, DBPROPSET** ppPropsets) const
    {
        CComPtr<IDBProperties> spProperties;

        // Check that we are connected
        ATLASSERT(m_spInit != NULL);

        HRESULT hr = m_spInit->QueryInterface(IID_IDBProperties, (void**)&spProperties);
        if (FAILED(hr))
            return hr;

        hr = spProperties->GetProperties(ulPropIDSets, pPropIDSet, pulPropertySets,
                ppPropsets);
        return hr;
    }

    HRESULT GetProperty(const GUID& guid, DBPROPID propid, VARIANT* pVariant) const
    {
        ATLASSERT(pVariant != NULL);
        CComPtr<IDBProperties> spProperties;

        // Check that we are connected
        ATLASSERT(m_spInit != NULL);

        HRESULT hr = m_spInit->QueryInterface(IID_IDBProperties, (void**)&spProperties);
        if (FAILED(hr))
            return hr;

        CDBPropIDSet set(guid);
        set.AddPropertyID(propid);
        DBPROPSET* pPropSet = NULL;
        ULONG ulPropSet = 0;
        hr = spProperties->GetProperties(1, &set, &ulPropSet, &pPropSet);
        if (FAILED(hr))
            return hr;

        ATLASSERT(ulPropSet == 1);
        VariantCopy(pVariant, &pPropSet->rgProperties[0].vValue);
        CoTaskMemFree(pPropSet->rgProperties);
        CoTaskMemFree(pPropSet);

        return S_OK;
    }
    void Close()
    {
        m_spInit.Release();
    }

// Implementation
    HRESULT OpenFromIDBProperties(IDBProperties* pIDBProperties)
    {
        CComPtr<IPersist> spPersist;
        CLSID   clsid;
        HRESULT hr;

        hr = pIDBProperties->QueryInterface(IID_IPersist, (void**)&spPersist);
        if (FAILED(hr))
            return hr;

        spPersist->GetClassID(&clsid);

        ULONG       ulPropSets=0;
        CDBPropSet* pPropSets=NULL;
        pIDBProperties->GetProperties(0, NULL, &ulPropSets, (DBPROPSET**)&pPropSets);

        hr = Open(clsid, &pPropSets[0], ulPropSets);

        for (ULONG i=0; i < ulPropSets; i++)
            (pPropSets+i)->~CDBPropSet();
        CoTaskMemFree(pPropSets);

        return hr;
    }
    HRESULT OpenWithNameUserPassword(LPCTSTR pName, LPCTSTR pUserName, LPCTSTR pPassword, long nInitMode = 0)
    {
        ATLASSERT(m_spInit != NULL);
        CComPtr<IDBProperties>  spProperties;
        HRESULT                 hr;

        hr = m_spInit->QueryInterface(IID_IDBProperties, (void**)&spProperties);
        if (FAILED(hr))
            return hr;

        // Set connection properties
        CDBPropSet propSet(DBPROPSET_DBINIT);

        // Add Datbase name, User name and Password
        if (pName != NULL)
            propSet.AddProperty(DBPROP_INIT_DATASOURCE, pName);

        if (pUserName != NULL)
            propSet.AddProperty(DBPROP_AUTH_USERID, pUserName);

        if (pPassword != NULL)
            propSet.AddProperty(DBPROP_AUTH_PASSWORD, pPassword);

        if (nInitMode)
            propSet.AddProperty(DBPROP_INIT_MODE, nInitMode);

        hr = spProperties->SetProperties(1, &propSet);
        if (FAILED(hr))
            return hr;

        // Initialize the provider
        return m_spInit->Initialize();
    }
    HRESULT OpenWithProperties(DBPROPSET* pPropSet, ULONG nPropertySets=1)
    {
        ATLASSERT(m_spInit != NULL);

        // Set the properties if there are some to set
        if (pPropSet != NULL)
        {
            CComPtr<IDBProperties>  spProperties;
            HRESULT                 hr;

            hr = m_spInit->QueryInterface(IID_IDBProperties, (void**)&spProperties);
            if (FAILED(hr))
                return hr;

            hr = spProperties->SetProperties(nPropertySets, pPropSet);
            if (FAILED(hr))
                return hr;
        }

        // Initialize the provider
        return m_spInit->Initialize();
    }

    CComPtr<IDBInitialize>  m_spInit;
};


///////////////////////////////////////////////////////////////////////////
// class CSession

class CSession
{
public:
    // Create a session on the passed datasource
    HRESULT Open(const CDataSource& ds)
    {
        CComPtr<IDBCreateSession> spSession;

        // Check we have connected to the database
        ATLASSERT(ds.m_spInit != NULL);

        HRESULT hr = ds.m_spInit->QueryInterface(IID_IDBCreateSession, (void**)&spSession);
        if (FAILED(hr))
            return hr;

        hr = spSession->CreateSession(NULL, IID_IOpenRowset, (IUnknown**)&m_spOpenRowset);
        return hr;
    }
    // Close the session
    void Close()
    {
        m_spOpenRowset.Release();
    }
    // Start a transaction
    HRESULT StartTransaction(ISOLEVEL isoLevel = ISOLATIONLEVEL_READCOMMITTED, ULONG isoFlags = 0,
        ITransactionOptions* pOtherOptions = NULL, ULONG* pulTransactionLevel = NULL) const
    {
        ATLASSERT(m_spOpenRowset != NULL);
        CComPtr<ITransactionLocal> spTransactionLocal;
        HRESULT hr = m_spOpenRowset->QueryInterface(&spTransactionLocal);

        if (SUCCEEDED(hr))
            hr = spTransactionLocal->StartTransaction(isoLevel, isoFlags, pOtherOptions, pulTransactionLevel);

        return hr;
    }
    // Abort the current transaction
    HRESULT Abort(BOID* pboidReason = NULL, BOOL bRetaining = FALSE, BOOL bAsync = FALSE) const
    {
        ATLASSERT(m_spOpenRowset != NULL);
        CComPtr<ITransaction> spTransaction;
        HRESULT hr = m_spOpenRowset->QueryInterface(&spTransaction);

        if (SUCCEEDED(hr))
            hr = spTransaction->Abort(pboidReason, bRetaining, bAsync);

        return hr;
    }
    // Commit the current transaction
    HRESULT Commit(BOOL bRetaining = FALSE, DWORD grfTC = XACTTC_SYNC, DWORD grfRM = 0) const
    {
        ATLASSERT(m_spOpenRowset != NULL);
        CComPtr<ITransaction> spTransaction;
        HRESULT hr = m_spOpenRowset->QueryInterface(&spTransaction);

        if (SUCCEEDED(hr))
            hr = spTransaction->Commit(bRetaining, grfTC, grfRM);

        return hr;
    }
    // Get information for the current transaction
    HRESULT GetTransactionInfo(XACTTRANSINFO* pInfo) const
    {
        ATLASSERT(m_spOpenRowset != NULL);
        CComPtr<ITransaction> spTransaction;
        HRESULT hr = m_spOpenRowset->QueryInterface(&spTransaction);

        if (SUCCEEDED(hr))
            hr = spTransaction->GetTransactionInfo(pInfo);

        return hr;
    }
// Implementation
    CComPtr<IOpenRowset> m_spOpenRowset;
};


///////////////////////////////////////////////////////////////////////////
// CTable

template <class TAccessor = CNoAccessor, class TRowset = CRowset>
class CTable :
    public CAccessorRowset<TAccessor, TRowset>
{
public:
    // Open a rowset on the passed name
    HRESULT Open(const CSession& session, LPCTSTR szTableName, DBPROPSET* pPropSet = NULL)
    {
        USES_CONVERSION;
        DBID    idTable;

        idTable.eKind           = DBKIND_NAME;
        idTable.uName.pwszName  = (LPOLESTR)T2COLE(szTableName);

        return Open(session, idTable, pPropSet);
    }
    // Open the a rowset on the passed DBID
    HRESULT Open(const CSession& session, DBID& dbid, DBPROPSET* pPropSet = NULL)
    {
        // Check the session is valid
        ATLASSERT(session.m_spOpenRowset != NULL);
        HRESULT hr;

        hr = session.m_spOpenRowset->OpenRowset(NULL, &dbid, NULL, GetIID(),
            (pPropSet) ? 1 : 0, pPropSet, (IUnknown**)GetInterfacePtr());
        if (SUCCEEDED(hr))
        {
            SetupOptionalRowsetInterfaces();

            // If we have output columns then bind
            if (_OutputColumnsClass::HasOutputColumns())
                hr = Bind();
        }

        return hr;
    }
};

#if (OLEDBVER < 0x0150)
#define DBGUID_DEFAULT DBGUID_DBSQL
#endif


///////////////////////////////////////////////////////////////////////////
// CCommandBase

class CCommandBase
{
public:
    CCommandBase()
    {
        m_hParameterAccessor = NULL;
    }

    ~CCommandBase()
    {
        ReleaseCommand();
    }
    // Create the command
    HRESULT CreateCommand(const CSession& session)
    {
        // Before creating the command, release the old one if necessary.
        ReleaseCommand();

        // Check the session is valid
        ATLASSERT(session.m_spOpenRowset != NULL);

        CComPtr<IDBCreateCommand> spCreateCommand;

        HRESULT hr = session.m_spOpenRowset->QueryInterface(IID_IDBCreateCommand, (void**)&spCreateCommand);
        if (FAILED(hr))
            return hr;

        return spCreateCommand->CreateCommand(NULL, IID_ICommand, (IUnknown**)&m_spCommand);
    }
    // Prepare the command
    HRESULT Prepare(ULONG cExpectedRuns = 0)
    {
        CComPtr<ICommandPrepare> spCommandPrepare;
        HRESULT hr = m_spCommand->QueryInterface(&spCommandPrepare);
        if (SUCCEEDED(hr))
            hr = spCommandPrepare->Prepare(cExpectedRuns);

        return hr;
    }
    // Unprepare the command
    HRESULT Unprepare()
    {
        CComPtr<ICommandPrepare> spCommandPrepare;
        HRESULT hr = m_spCommand->QueryInterface(&spCommandPrepare);
        if (SUCCEEDED(hr))
            hr = spCommandPrepare->Unprepare();

        return hr;
    }
    // Create the command and set the command text
    HRESULT Create(const CSession& session, LPCTSTR szCommand,
        REFGUID guidCommand = DBGUID_DEFAULT)
    {
        USES_CONVERSION;
        HRESULT hr;

        hr = CreateCommand(session);
        if (SUCCEEDED(hr))
        {
            CComPtr<ICommandText> spCommandText;
            hr = m_spCommand->QueryInterface(&spCommandText);
            if (SUCCEEDED(hr))
                hr = spCommandText->SetCommandText(guidCommand, T2COLE(szCommand));
        }
        return hr;
    }
    // Release the command
    void ReleaseCommand()
    {
        // Release the parameter accessor if necessary, before releasing the command
        if (m_hParameterAccessor != NULL)
        {
            CComPtr<IAccessor> spAccessor;
            HRESULT hr = m_spCommand->QueryInterface(&spAccessor);
            if (SUCCEEDED(hr))
            {
                spAccessor->ReleaseAccessor(m_hParameterAccessor, NULL); \
                m_hParameterAccessor = NULL;
            }
        }
        m_spCommand.Release();
    }
    // Get the parameter information from the command
    HRESULT GetParameterInfo(ULONG* pParams, DBPARAMINFO** ppParamInfo,
                OLECHAR** ppNamesBuffer)
    {
        CComPtr<ICommandWithParameters> spCommandParameters;
        HRESULT hr = m_spCommand->QueryInterface(&spCommandParameters);
        if (SUCCEEDED(hr))
        {
            // Get the parameter information
            hr = spCommandParameters->GetParameterInfo(pParams, ppParamInfo,
                    ppNamesBuffer);
        }
        return hr;
    }
    // Set the parameter information for the command
    HRESULT SetParameterInfo(ULONG ulParams, const ULONG* pOrdinals,
                const DBPARAMBINDINFO* pParamInfo)
    {
        CComPtr<ICommandWithParameters> spCommandParameters;
        HRESULT hr = m_spCommand->QueryInterface(&spCommandParameters);
        if (SUCCEEDED(hr))
        {
            // Set the parameter information
            hr = spCommandParameters->SetParameterInfo(ulParams, pOrdinals,
                pParamInfo);
        }
        return hr;
    }

    CComPtr<ICommand>   m_spCommand;
    HACCESSOR           m_hParameterAccessor;
};

// Used to turn on multiple result set support in CCommand
class CMultipleResults
{
public:
    bool UseMultipleResults() { return true; }
    IMultipleResults** GetMultiplePtrAddress() { return &m_spMultipleResults.p; }
    IMultipleResults* GetMultiplePtr() { return m_spMultipleResults; }

    CComPtr<IMultipleResults> m_spMultipleResults;
};

// Used to turn off multiple result set support in CCommand
class CNoMultipleResults
{
public:
    bool UseMultipleResults() { return false; }
    IMultipleResults** GetMultiplePtrAddress() { return NULL; }
    IMultipleResults* GetMultiplePtr() { return NULL; }
};


///////////////////////////////////////////////////////////////////////////
// CCommand

template <class TAccessor = CNoAccessor, class TRowset = CRowset, class TMultiple = CNoMultipleResults>
class CCommand :
    public CAccessorRowset<TAccessor, TRowset>,
    public CCommandBase,
    public TMultiple
{
public:
    // Create a command on the session and execute it
    HRESULT Open(const CSession& session, LPCTSTR szCommand = NULL,
        DBPROPSET *pPropSet = NULL, LONG* pRowsAffected = NULL,
        REFGUID guidCommand = DBGUID_DEFAULT, bool bBind = true)
    {
        HRESULT hr;
        if (szCommand == NULL)
        {
            hr = _CommandClass::GetDefaultCommand(&szCommand);
            if (FAILED(hr))
                return hr;
        }
        hr = Create(session, szCommand, guidCommand);
        if (FAILED(hr))
            return hr;

        return Open(pPropSet, pRowsAffected, bBind);
    }
    // Used if you have previously created the command
    HRESULT Open(DBPROPSET *pPropSet = NULL, LONG* pRowsAffected = NULL, bool bBind = true)
    {
        HRESULT     hr;
        DBPARAMS    params;
        DBPARAMS    *pParams;

        // Bind the parameters if we have some
        if (_ParamClass::HasParameters())
        {
            // Bind the parameters in the accessor if they haven't already been bound
            hr = BindParameters(&m_hParameterAccessor, m_spCommand, ¶ms.pData);
            if (FAILED(hr))
                return hr;

            // Setup the DBPARAMS structure
            params.cParamSets = 1;
            params.hAccessor = m_hParameterAccessor;
            pParams = ¶ms;
        }
        else
            pParams = NULL;

        hr = Execute(GetInterfacePtr(), pParams, pPropSet, pRowsAffected);
        if (FAILED(hr))
            return hr;

        // Only bind if we have been asked to and we have output columns
        if (bBind && _OutputColumnsClass::HasOutputColumns())
            return Bind();
        else
            return hr;
    }
    // Get the next rowset when using multiple result sets
    HRESULT GetNextResult(LONG* pulRowsAffected, bool bBind = true)
    {
        // This function should only be called if CMultipleResults is being
        // used as the third template parameter
        ATLASSERT(GetMultiplePtrAddress() != NULL);

        // If user calls GetNextResult but the interface is not available
        // return E_FAIL.
        if (GetMultiplePtr() == NULL)
            return E_FAIL;

        // Close the existing rowset in preparation for opening the next one
        Close();

        HRESULT hr = GetMultiplePtr()->GetResult(NULL, 0, IID_IRowset,
            pulRowsAffected, (IUnknown**)GetInterfacePtr());
        if (FAILED(hr))
            return hr;

        if (bBind && GetInterface() != NULL)
            return Bind();
        else
            return hr;
    }

// Implementation
    HRESULT Execute(IRowset** ppRowset, DBPARAMS* pParams, DBPROPSET *pPropSet, LONG* pRowsAffected)
    {
        HRESULT hr;

        // Specify the properties if we have some
        if (pPropSet)
        {
            CComPtr<ICommandProperties> spCommandProperties;
            hr = m_spCommand->QueryInterface(&spCommandProperties);
            if (FAILED(hr))
                return hr;

            hr = spCommandProperties->SetProperties(1, pPropSet);
            if (FAILED(hr))
                return hr;
        }

        // If the user want the rows affected then return it back, otherwise
        // just point to our local variable here.
        LONG nAffected, *pAffected;
        if (pRowsAffected)
            pAffected = pRowsAffected;
        else
            pAffected = &nAffected;

        if (UseMultipleResults())
        {
            hr = m_spCommand->Execute(NULL, IID_IMultipleResults, pParams,
                pAffected, (IUnknown**)GetMultiplePtrAddress());

            if (SUCCEEDED(hr))
            {
                hr = GetNextResult(pAffected, false);
            }
            else
            {
                // If we can't get IMultipleResults then just try to get IRowset
                hr = m_spCommand->Execute(NULL, IID_IRowset, pParams, pAffected,
                    (IUnknown**)GetInterfacePtr());
            }
        }
        else
        {
            hr = m_spCommand->Execute(NULL, GetIID(), pParams, pAffected,
                (IUnknown**)ppRowset);
            if (SUCCEEDED(hr))
                SetupOptionalRowsetInterfaces();
        }
        return hr;
    }
};


// This class can be used to implement the IRowsetNotify interface.
// It is supplied so that if you only want to implement one of the
// notifications you don't have to supply empty functions for the
// other methods.
class ATL_NO_VTABLE IRowsetNotifyImpl : public IRowsetNotify
{
public:
    STDMETHOD(OnFieldChange)(
            /* [in] */ IRowset* /* pRowset */,
            /* [in] */ HROW /* hRow */,
            /* [in] */ ULONG /* cColumns */,
            /* [size_is][in] */ ULONG /* rgColumns*/ [] ,
            /* [in] */ DBREASON /* eReason */,
            /* [in] */ DBEVENTPHASE /* ePhase */,
            /* [in] */ BOOL /* fCantDeny */)
    {
        ATLTRACENOTIMPL(_T("IRowsetNotifyImpl::OnFieldChange"));
    }
    STDMETHOD(OnRowChange)(
            /* [in] */ IRowset* /* pRowset */,
            /* [in] */ ULONG /* cRows */,
            /* [size_is][in] */ const HROW /* rghRows*/ [] ,
            /* [in] */ DBREASON /* eReason */,
            /* [in] */ DBEVENTPHASE /* ePhase */,
            /* [in] */ BOOL /* fCantDeny */)
    {
        ATLTRACENOTIMPL(_T("IRowsetNotifyImpl::OnRowChange"));
    }
    STDMETHOD(OnRowsetChange)(
        /* [in] */ IRowset* /* pRowset */,
        /* [in] */ DBREASON /* eReason */,
        /* [in] */ DBEVENTPHASE /* ePhase */,
        /* [in] */ BOOL /* fCantDeny*/)
    {
        ATLTRACENOTIMPL(_T("IRowsetNotifyImpl::OnRowsetChange"));
    }
};

}; //namespace ATL

#endif // __ATLDBCLI_H_