using TRDSConnection component in Delphi

Question

Someone can explain me what is the use of ADO component TRDSConnection.y give an small example of use.

Thanks in advance.

Answer 1

RDS is a multi-tier solution provided by Microsoft in ADO. You can use TRDSConnection in your client application to connect to an application server (middle-tier) which is responsible for retrieving data from your database server (back end tier).

The idea behind it is similar to using DatasetProvider and ClientDataset in your DataSnap applications.

You can read more about RDS in MSDN entry for ADO.

Answer 2

From MS doc: The Microsoft Remote Data Service (RDS) allows you to use an ADO recordset remotely across one of three protocols (HTTP, HTTPS, or DCOM). RDS was originally intended for Web-based clients, but you are free to implement your RDS client in any development environment or language you choose. You can optionally implement a server side business object for generating and receiving a recordset, or you can use the default business object that RDS provides within its server-side components. You are required to use Internet Information Server (IIS) to host the RDS Server components only if using the HTTP or HTTPS protocols. Using DCOM to marshal objects (recordset or otherwise) with RDS eliminates the IIS dependency. RDS provides the advantages of client-side caching of data results, updateable data, and support for some data-aware ActiveX controls.

RDS demo (Up to Delphi2007): in ...Documents\RAD Studio\5.0\DEmos\DelphiWin32\VCL\ADO\RDS for D2007.
Very rudimentary server and client (look in Appserver.pas and ClientMain.pas). You can try and combine it with the AdoTest Demo in the sibling folder.

see also:
http://edn.embarcadero.com/article/28502
http://msdn.microsoft.com/en-us/library/ms676550%28VS.85%29.aspx
http://msdn.microsoft.com/en-us/library/ms677528%28VS.85%29.aspx

Note: Do not forget to modify Windows\MSDFMAP.INI as indicated in ClientMain.pas