teCommand, ( void** )&pICreateCommand );
        if( FAILED( hResult ) )
        {
            return hResult;
        }
  
        hResult = pICreateCommand->CreateCommand( NULL, IID_ICommand, (IUnknown**)&pICommand );
        if( FAILED( hResult ) )
        {
            return hResult;
        }
    }
    EAutoReleasePtr<ICommandText> pICommandText;
    hResult = pICommand->QueryInterface( &pICommandText );
    if( FAILED( hResult ) )
    {
        return hResult;
    }
    * ppICommand = pICommand.Detach( );
    * ppICommandText = pICommandText.Detach( );
    return S_OK;
}

HRESULT ExecuteSQL( ICommand* pICommand, ICommandText* pICommandText, LPCTSTR pszCommand, LONG* plRowsAffected )
{
    ASSERT( pICommand != NULL && pICommandText != NULL && pszCommand != NULL && pszCommand[0] != 0 );

    HRESULT hResult = pICommandText->SetCommandText( DBGUID_DBSQL, ( LPCOLESTR )pszCommand );
    if( FAILED( hResult ) )
    {
        return hResult;
    }
    LONG lAffected;
    hResult = pICommand->Execute( NULL, IID_NULL, NULL, plRowsAffected == NULL ? &lAffected : plRowsAffected, ( IUnknown** )NULL );
    return hResult;
}

以上就是写数据库的全部代码了，是不是很简单呢？下面再来读的。

// 先用与上面代码中一样的步骤获取pICommand，pICommandText。此处省略

HRESULT hResult = pICommandText->SetCommandText( DBGUID_DBSQL, ( LPCOLESTR )_T("SELECT Volume FROM 2005_1 WHERE ID = @@IDENTITY") ); //取我们刚刚添加的那一条记录
if( FAILED( hResult ) )
{
    return;
}

LONG lAffected;
EAutoReleasePtr<IRowset> pIRowset;
hResult = pICommand->Execute( NULL, IID_IRowset, NULL, &lAffected, ( IUnknown** )&pIRowset );

if( FAILED( hResult ) )
{
    return;
}

EAutoReleasePtr<IAccessor> pIAccessor;
hResult = pIRowset->QueryInterface( IID_IAccessor, ( void** )&pIAccessor );

if( FAILED( hResult ) )
{
    return;
}

// 一个根据表中各字段的数值类型而定义的结构，用于存储返回的各字段的值
struct CLoadLastFromDB
{
     DBSTATUS dwdsVolume;
     DWORD     dwLenVolume;
     f