Article ID: 165804
Article Last Modified on 3/2/2005
APPLIES TO
- Microsoft Internet Information Server 3.0
- Microsoft Internet Information Server 4.0
- Microsoft Remote Data Services 1.5
- Remote Data Service for ADO 2.0
- Microsoft Remote Data Services 2.1
This article was previously published under Q165804
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:
165297RDS: 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:
166277 HOWTO: Create a VB Component that Returns a Recordset in RDS
183294 Techniques for Returning a Recordset via RDS
183609 Rdsvb.exe Demonstrates How to Use RDS with Visual Basic
183628 HOWTO: Using the RDS DataFactory via Standard ADO Open Method
184606 HOWTO: Use RDS From an IIS 4.0 Virtual Server
The Remote Data Service Web site located at the following URL:
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.
Keywords: kbinfo kbdatabase KB165804
