KB165804 - INFO: Comparing RDS Technology to RDO and DAO

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:

http://msdn.microsoft.com/dataaccessado/rds/default.htm

SUMMARY

NOTE

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.