loat          fVolume;
};

// 此处我们只查询了一个字段。如果要查询多个字段，CLoadLastFromDB中要添加相应的字段定义，下面的dbBinding也要相应扩充。dbBinding.iOrdinal要分别指向各个字段，dbBinding.wType要根据字段类型赋合适的值。

DBBINDING dbBinding;
dbBinding[0].iOrdinal            = 1;   // Volume 字段的位置，从 1 开始
dbBinding[0].obValue           = offsetof( CLoadLastFromDB, fVolume );
dbBinding[0].obLength         = offsetof( CLoadLastFromDB, dwLenVolume );
dbBinding[0].obStatus         = offsetof( CLoadLastFromDB, dwdsVolume );
dbBinding[0].pTypeInfo       = NULL;
dbBinding[0].pObject           = NULL;
dbBinding[0].pBindExt         = NULL;
dbBinding[0].dwPart            = DBPART_VALUE | DBPART_STATUS | DBPART_LENGTH;
dbBinding[0].dwMemOwner = DBMEMOWNER_CLIENTOWNED;
dbBinding[0].eParamIO       = DBPARAMIO_NOTPARAM;
dbBinding[0].cbMaxLen       = 0;
dbBinding[0].dwFlags          = 0;
dbBinding[0].wType            = DBTYPE_R4; // float就是DBTYPE_R4，int就是DBTYPE_I4。参见MSDN
dbBinding[0].bPrecision       = 0;
dbBinding[0].bScale             = 0;

HACCESSOR hAccessor = DB_NULL_HACCESSOR;
DBBINDSTATUS dbs;
hResult = pIAccessor->CreateAccessor( DBACCESSOR_ROWDATA, 1, dbBinding, sizeof( CLoadLastDataFromDB ), &hAccessor, dbs );

if( FAILED( hResult ) )
{
    return;
}

ASSERT( dbs[0] == DBBINDSTATUS_OK );
ULONG uRowsObtained = 0;
HROW  hRows;                          // 这里我们只查询了最新的那一条记录
HROW* phRows = hRows;
CLoadLastFromDB rmd;
hResult = pIRowset->GetNextRows( NULL, 0, 1, &uRowsObtained, &phRows );
if( SUCCEEDED( hResult ) && uRowsObtained != 0U )
{
    hResult = pIRowset->GetData( phRows[0], hAccessor, &rmd );
    if( FAILED( hResult ) )
    {
        ASSERT( FALSE );
    }
    ASSERT( rmd.dwdsVolume == DBSTATUS_S_OK );
    // rmd.fVolume 就是我们要取的值
}

pIRowset->ReleaseRows( uRowsObtained, phRows, NULL, NULL, NULL );
pIAccessor->ReleaseAccessor( hAccessor, NULL );
pIAccessor.Release( );
pI