RDS Tutorial

This tutorial illustrates using the RDS programming model to query and update a data source. A common description of the steps necessary to accomplish this task is presented in English. Then the tutorial is repeated in the Visual Basic, VBScript, and Visual J++ (featuring ADO for Java) programming languages.

This tutorial is coded in different languages for two reasons:

• The documentation for RDS assumes the reader codes in Visual Basic. This makes the documentation convenient for Visual Basic programmers, but less useful for programmers who use other languages.
  
  
• If you are uncertain about a particular RDS feature and you know a little of another language, you may be able to resolve your question by looking for the same feature expressed in another language.

How the Tutorial is Presented

This tutorial is based on the RDS programming model. We will go through the programming model step-by-step, pausing to discuss each step. In addition, we will illustrate each step with a fragment of Visual Basic code.

The code example is repeated in other languages with minimal discussion. Each step in a given programming language tutorial is marked with the corresponding step in the programming model and English language tutorial. Use the number of the step to refer to the discussion in the English language tutorial.

The RDS programming model is stated below. We'll restate it, and use it like a roadmap as you go through the tutorial.

RDS Programming Model with Objects

1. Specify the program to be invoked on the server, and obtain a way (proxy) to refer to it from the client. (RDS.DataSpace)
   
   
2. Invoke the server program. Pass parameters to the server program that identify the data source and the command to issue. (proxy or RDS.DataControl)
   
   
3. The server program obtains a Recordset object from the data source, typically by using ADO. Optionally, the Recordset object is processed on the server. (RDSServer.DataFactory)
   
   
4. The server program returns the final Recordset object to the client application. (proxy)
   
   
5. On the client, the Recordset object is optionally put into a form that can be easily used by visual controls. (visual control and RDS.DataControl)
   
   
6. Changes to the Recordset object are sent back to the server and used to update the data source. (RDS.DataControl or RDSServer.DataFactory)