Beginning Access™ 2007 VBA

8.1. Introduction to Web Services

A common topic of discussion in the high-tech sector these days is web services. Web services are reusable components that are based on standard Internet protocols. They enable systems on different platforms to talk to each other. In the simplest terms, I like to describe a web service as some procedure or function that someone has made available over Internet protocols so that you can use it for free or for a cost. Web services can be called (consumed) by Web and non-Web-based applications as long as the application can communicate using standard Internet protocols. Web services typically return a response in XML format that can then be used appropriately in the consuming program.

Although web services communicate using Internet protocols, you can still use web services for private purposes within a company. For example, some companies are better integrating legacy mainframe and other applications into their current environment by exposing parts of the old application as a web service. After the old application is made accessible using a web service, it can be called from other platforms that, traditionally, could not communicate easily. Although I could write a whole chapter or even a book on web services alone, I want you, at least, to learn the basic concept of what a web service is. I also want to give you a simple example of how you can use someone else's web service in your Access applications. The first part of this chapter will show you ...