In this final chapter, we've seen how we can interchange layers in an application without affecting the way it is built, and without having to know how it works underneath. Our new public Web application interface uses the same
component to get-up-to-date information about the cars we stock, and the same SQL Server stored procedure to get the color details, as the Web-based and Visual Basic interfaces we designed for use in our car showrooms did.WCCCars
It also places the order using the same ASP page as the showroom application, and so the order is processed in exactly the same way. We can even run the showroom order monitor application from anywhere on the Web to get information about head office acceptance of the orders.
This freedom to interchange interfaces with business functions is one of the core concepts of the Distributed interNet Applications (DNA) architecture, and one of its major advantages when it comes to building distributed applications. Because of the Component Object Model (COM), all our components, ASP scripts, services and other objects can communicate very easily in standardized formats and across widely distributed networks.
We've come to the end of the book, and with it our exploration of DNA, Components, Microsoft Transaction Server and Microsoft Message Queue Server. To learn more about any of these topics, including the way they can be implemented in other languages like C++, Java, JavaScript, VBScript and Visual Basic, visit our Web Developer Resources and Reference site at
, and our main Wrox Press Books sites at http://rapid.wrox.co.uk/
and http://www.wrox.com/
/.http://www.wrox.co.uk