DOCUMENT:Q165804 06-JUL-2001 [iis] TITLE :INFO: Comparing RDS Technology to RDO and DAO PRODUCT :Internet Information Server PROD/VER:WINDOWS:1.5,2.0,2.1 SP2; winnt:3.0,4.0 OPER/SYS: KEYWORDS:kbDatabase kbRDS150 kbRDS200 kbGrpDSVBDB kbGrpDSMDAC kbDSupport kbRDS210SP2 ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Internet Information Server versions 3.0, 4.0 - Remote Data Service for ADO versions 1.5, 2.0, 2.1 SP2 ------------------------------------------------------------------------------- SUMMARY ======= NOTE: With version 1.5, the Remote Data Service (RDS) was renamed and merged with ActiveX Data Objects (ADO) to provide data remoting within the same programming model as ADO. Formerly, the Remote Data Service was known as the Advanced Data Connector (ADC). To clarify the relationship of ADC to ADO, ADC is now known as the Remote Data Service (RDS), a feature of ADO Web Data Access Feature of the ActiveX Data Objects (ADO). Q. Is the Remote Data Service superior to RDO and DAO in getting at SQL data in a client-server application? A. RDO and DAO are designed for a persistent sockets/pipes connection to your database server. The Remote Data Service (RDS) works disconnected through HTTP over your intranet or the Internet through firewalls. RDS also works over the Distributed Component Object Model (DCOM) but this discussion focuses on HTTP. RDS passes a disconnected recordset to the client. This is a completely stateless model, which means the server could actually be shut down and restarted between RDS client requests. This is done through a Mime64 encoded Advanced Data Tablegram (ADTG) passed to the client, which then opens it and loads it into a client-side Virtual Table Manager (VTM). At this time the client can walk the recordset, perform updates, and send the changes back to the server for base table updates. RDO and DAO work in-process on the local computer or possibly over a LAN through DCOM if you wrap their functionality in a Visual Basic ActiveX EXE. Currently DCOM does not support transport over HTTP so it is impossible to pass a recordset through a firewall. Attempting to marshal a recordset and its interfaces over DCOM to the client is also unacceptably slow and will ultimately fail. Your alternative is to pass the recordset from the server to the client as a variant array (GetRows), which works well, but is very primitive compared to RDS technology. RDS also provides the support necessary to bind to data-aware OCXs in Microsoft Internet Explorer version 3.0 and later, support that is not built into Internet Explorer 3.0. This data binding functionality is very similar to the Visual Basic Data Control and Remote Data Control, which require very little or no code. REFERENCES ========== For a more detailed example of this code, please see the following article in the Microsoft Knowledge Base: Q165297RDS: How To Use From Inside a Visual Basic Program For additional information, please click the article numbers below to view the articles in the Microsoft Knowledge Base: Q166277 HOWTO: Create a VB Component that Returns a Recordset in RDS Q183294 Techniques for Returning a Recordset via RDS Q183609 Rdsvb.exe Demonstrates How to Use RDS with Visual Basic Q183628 HOWTO: Using the RDS DataFactory via Standard ADO Open Method Q184606 HOWTO: Use RDS From an IIS 4.0 Virtual Server The Remote Data Service Web site located at the following URL: http://www.microsoft.com/data/ado/rds/default.htm RDS Help, Mrds10.hlp (contained in the self-extracting RDS installation file, Mrds10.exe). (c) Microsoft Corporation 1997, All Rights Reserved. Contributions by Jon Fowler, Microsoft Corporation. Additional query words: ====================================================================== Keywords : kbDatabase kbRDS150 kbRDS200 kbGrpDSVBDB kbGrpDSMDAC kbDSupport kbRDS210SP2 Technology : kbiisSearch kbAudDeveloper kbADOsearch kbiis400 kbiis300 kbRDSSearch kbRDS150 kbRDS200 kbRDS210SP2 Version : WINDOWS:1.5,2.0,2.1 SP2; winnt:3.0,4.0 Issue type : kbinfo ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.