.dwPart     =  DBPART_VALUE | DBPART_STATUS | DBPART_LENGTH;
dbBinding.dwMemOwner = DBMEMOWNER_CLIENTOWNED;
dbBinding.eParamIO   = DBPARAMIO_NOTPARAM;
dbBinding.cbMaxLen   = 0;
dbBinding.dwFlags    = 0;
dbBinding.wType      = DBTYPE_IUNKNOWN;
dbBinding.bPrecision = 0;
dbBinding.bScale     = 0;

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

EAutoReleasePtr<IRowset> pIRowset;
hResult = pIRowsetChange->QueryInterface( IID_IRowset, ( void** )&pIRowset );

ULONG uRowsObtained = 0;
HROW* phRows = NULL;
hResult = pIRowset->GetNextRows( NULL, 0, 1, &uRowsObtained, &phRows );

CSequentialStream* pss = new CSequentialStream;
pss->PreAllocBuffer( 1024 );                           // 预先分配好内存，并读入数据
pss->Write( pszSomebuffer, 512, NULL );        // pss->Write可以连续调用
pss->Write( pszSomebuffer+512, 512, NULL );
pss->ResetPosition( );

BLOBDATA bd;
bd.pISeqStream = ( ISequentialStream* )pss;
bd.dwStatus    = DBSTATUS_S_OK;
bd.dwLength    = pss->GetLength( );

// 将 BLOB 数据写入到数据库
hResult = pIRowsetChange->SetData( phRows[0], hAccessor, &bd );

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

// pss was released by pIRowsetChange->SetData.

这样，我们就完成了一条记录的添加。读取BLOB字段的代码跟上面的完全类似，只要把
hResult = pIRowset->GetNextRows( NULL, 0, 1, &uRowsObtained, &phRows );
后面的那些改成下面的代码即可。

BLOBDATA bd;
hResult = pIRowset->GetData( phRows[0], hAccessor, &bd );
if( bd.dwStatus == DBSTATUS_S_ISNULL )
{
    // 此字段为空
}
else if( bd.dwStatus != DBSTATUS_S_OK || bd.pISeqStream == NULL )
{
    // 失败
}
else
{
    // 从系统分配的 ISequentialStream 接口读入 BLOB 数据
    BYTE szReadBuffer[1024];
    for( ULONG uRead = 0U; ; )
    {
        if( FAILED( bd.pISeqStream->Read( szReadBuffer, 1024, &uRead ) ) )
        {
            break;
        }
        //szReadBuffer中就包含了BLOB字段的数据
        if( uRead != 1024 )
        {
            break;