openingadorecordsetwithcom.cpp

vc ADO 连接数据库

#include <windows.h>
#include <initguid.h>  // Include only once in your application
#include "adoid.h"     // ADO GUID's
#include "adoint.h"    // ADO Classes, enums, etc.

struct InitOle {
InitOle()  { ::CoInitialize(NULL); }
~InitOle() { ::CoUninitialize();   }
} _init_InitOle_;

void main()
{
    HRESULT         hr  = S_OK;
    ADORecordset*   Rs1 = NULL;
    VARIANT         Source;
    VARIANT         Connect;

    VariantInit( &Source  );
    VariantInit( &Connect );

    Source.vt       = VT_BSTR;
    Source.bstrVal  = ::SysAllocString( L"SELECT * FROM Authors");

    Connect.vt      = VT_BSTR;
    Connect.bstrVal = ::SysAllocString( L"DSN=AdoDemo;UID=admin;PWD=;" );

    hr = CoCreateInstance( CLSID_CADORecordset, 
                           NULL, 
                           CLSCTX_INPROC_SERVER, 
                           IID_IADORecordset, 
                           (LPVOID *) &Rs1 );

    if( SUCCEEDED( hr ) ) hr = Rs1->Open( Source,
                                          Connect,
                                          adOpenForwardOnly, 
                                          adLockReadOnly, 
                                          -1 );
    if( SUCCEEDED( hr ) ) hr = Rs1->Close();
    if( SUCCEEDED( hr ) ) { Rs1->Release();  Rs1 = NULL; }
    if( SUCCEEDED( hr ) ) ::MessageBox( NULL, "Success!", "", MB_OK );
}