OLEDB: Prepared cmd with NULL input param for NOT NULL INT..

Provider: SQLOLEDB
Version: SQL Server 2000 8.00.760

Script for creating table:

CREATE TABLE [dbo].[ADRVERTRETER] (
  [ROWID] [timestamp] NULL ,
  [ROWVERTRETER] [int] NOT NULL ,
  [FIRMA] [smallint] NOT NULL ,
  [VERTRETER] [int] NOT NULL ,
  [NAME] [varchar] (20) COLLATE Latin1_General_CS_AS NULL ,
  [ROWADRESSEN] [int] NULL ,
  [PROVISION] [decimal](14, 2) NULL ,
  [STEUERKZ] [smallint] NULL ,
  [MITARBEITER] [int] NULL
) ON [PRIMARY]
GO

Command:
select NAME from ADRVERTRETER where VERTRETER = ?

When i execute the above command with a NULL parameter , i get the error:
"Invalid Input Parameter Value. Check Status Value for details"
If the unprepared command is executed , it does not give an error.

I am giving my test code below:

void main()
{


  HRESULT hr;
  CLSID clsid;
  ICommandText *pICommandText = NULL;
  ICommand *pICommand = NULL;
  IDBCreateSession *pIDBCreateSession = NULL;
  IDBCreateCommand *pIDBCreateCommand = NULL;
  IDBInitialize *pIDBInitialize = NULL;
  IDBProperties *pIDBProperties = NULL;
  ICommandPrepare *pICommandPrepare = NULL;
  ICommandWithParameters *pICommandWithParameters = NULL;
  IRowset *pIRowset = NULL;
  ICommandProperties *pICommandProperties = NULL;
  IAccessor *pIAccessor;
  HACCESSOR hAccessor;

  const ULONG nProps = 1;
  LONG cRowsAffected;
  DBBINDSTATUS* rgStatus = NULL;
  DBBINDSTATUS *pRowStatus = NULL;
  DBPROP InitProperties[ nProps ];
  DBPROPSET rgInitPropSet;


  DBPARAMS m_Params;
  DBBINDING ParamBinding[1];


  InitProperties[ 0 ].dwPropertyID = DBPROP_INIT_PROVIDERSTRING;
  InitProperties[ 0 ].vValue.vt = VT_BSTR;
  InitProperties[ 0 ].dwOptions = DBPROPOPTIONS_REQUIRED;
  InitProperties[ 0 ].colid = DB_NULLID;
  InitProperties[ 0 ].dwStatus = DBPROPSTATUS_OK;
  InitProperties[ 0 ].vValue.bstrVal =
  SysAllocString( OLESTR( "SERVER=son1205;DATABASE=pubs;uid=sa;pwd=sa;" ) );

  rgInitPropSet.guidPropertySet = DBPROPSET_DBINIT;
  rgInitPropSet.cProperties = nProps;
  rgInitPropSet.rgProperties = InitProperties;

  if( FAILED( hr = CoInitialize( NULL ) ) )
  {
   printf( "CoInitialize failed\n " );
   return;
  }

  hr = CLSIDFromProgID( L"SQLOLEDB", & clsid );

  if( FAILED( hr = CoCreateInstance( clsid,
   NULL,
   CLSCTX_INPROC_SERVER,
   IID_IDBInitialize,
   ( void ** ) & pIDBInitialize ) ) )
  {
   printf( "CoCreateInstance failed\n " );
   return;
  }

  hr = pIDBInitialize->QueryInterface( IID_IDBProperties,
   ( void ** ) & pIDBProperties );
  hr = pIDBProperties->SetProperties( 1, & rgInitPropSet );
  SysFreeString( InitProperties[ 0 ].vValue.bstrVal );
  pIDBProperties->Release();
  if( FAILED( hr = pIDBInitialize->Initialize() ) )
  {
   printf( "Failed to initializa Database\n " );
   return;
  }
  hr = pIDBInitialize->QueryInterface( IID_IDBCreateSession,
   ( void ** ) & pIDBCreateSession );

  if( FAILED( hr = pIDBCreateSession->CreateSession( NULL,
   IID_IDBCreateCommand,
   ( IUnknown ** ) & pIDBCreateCommand ) ) )
  {
   printf( "Session Initialization failed\n " );
   return;
  }

  if( FAILED( hr = pIDBCreateCommand->CreateCommand( NULL,
   IID_ICommand,
   ( IUnknown ** ) & pICommand ) ) )
  {
   printf( "Create Command failed\n " );
   return;
  }

  pIDBCreateCommand->Release();


  DBLENGTH cbRowSize = 0;
  ParamBinding[ 0 ].iOrdinal = 1;
  ParamBinding[ 0 ].obStatus = cbRowSize;
  cbRowSize += ROUNDUP(sizeof(DBSTATUS));
  ParamBinding[ 0 ].obLength = cbRowSize;
  cbRowSize += ROUNDUP(sizeof(DBLENGTH));
  ParamBinding[ 0 ].obValue = cbRowSize;
  ParamBinding[ 0 ].pTypeInfo = NULL;
  ParamBinding[ 0 ].pBindExt = NULL;
  ParamBinding[ 0 ].dwPart = DBPART_VALUE | DBPART_STATUS | DBPART_LENGTH;
  ParamBinding[ 0 ].dwMemOwner = DBMEMOWNER_CLIENTOWNED;
  ParamBinding[ 0 ].eParamIO = DBPARAMIO_INPUT;
  ParamBinding[ 0 ].dwFlags = 0;
  ParamBinding[ 0 ].bPrecision = 0;
  ParamBinding[ 0 ].bScale = 0;
  ParamBinding[ 0 ].pObject = NULL;
  ParamBinding[ 0 ].wType = DBTYPE_NUMERIC;
  ParamBinding[ 0 ].cbMaxLen = 19;

  cbRowSize += ParamBinding[ 0 ].cbMaxLen;
  cbRowSize = ROUNDUP( cbRowSize );

  WCHAR* wSQLString = L"select NAME from ADRVERTRETER where VERTRETER = ?";

  hr = pICommand->QueryInterface( IID_ICommandText, ( void ** ) &
pICommandText );



  hr = pICommandText->SetCommandText( DBGUID_DBSQL, wSQLString );

  hr = pICommandText->QueryInterface( IID_IAccessor,
  ( void ** ) & pIAccessor );

  SAFE_ALLOC(rgStatus, DBBINDSTATUS, 1);

  hr = pIAccessor->CreateAccessor( DBACCESSOR_PARAMETERDATA,1,
   ParamBinding,
   sizeof( ParamBinding ),
   & hAccessor,
   rgStatus );

  SAFE_FREE(rgStatus);

  m_Params.cParamSets = 1;
  m_Params.hAccessor = hAccessor;


  //Also allocate memory
  SAFE_ALLOC(m_Params.pData, BYTE, cbRowSize);

  void* pValue = VALUE_IS_BOUND(ParamBinding[0]) ?
&BINDING_VALUE(ParamBinding[0], m_Params.pData) : NULL;

  if(STATUS_IS_BOUND(ParamBinding[0]))
   BINDING_STATUS(ParamBinding[0], m_Params.pData) = DBSTATUS_S_ISNULL;
  if(LENGTH_IS_BOUND(ParamBinding[0]))
   BINDING_LENGTH(ParamBinding[0], m_Params.pData) = 0;


  hr = pICommand->QueryInterface( IID_ICommandPrepare,
  (LPVOID*) &pICommandPrepare);

  if( SUCCEEDED( hr ) )
  hr = pICommandPrepare->Prepare( 0 );

  pICommandPrepare->Release();
  IRowset *pRowset = NULL;
  hr = pICommand->Execute( NULL,
   IID_IRowset,
   &m_Params,
   & cRowsAffected,
   (LPUNKNOWN *)&pRowset );

  if(FAILED(hr))
   GetError(pICommand,hr);

  m_Params.cParamSets = 0;
  SAFE_FREE(m_Params.pData);


  pIAccessor->ReleaseAccessor( hAccessor, NULL );
  pIAccessor->Release();
  pICommandText->Release();
  pICommand->Release();
  pIDBCreateSession->Release();
  pIDBInitialize->Release();
  CoUninitialize();
}

Please let me know if there is any error in th ecode.

Thanks

Neophyte