Web based School

Appendix C

Visual InterDev Architecture Components Overview

Visual InterDev consists of a very robust architecture that provides many capabilities to support your application development. This appendix is provided as a supplement to the guide to focus on the architecture of Visual InterDev. The information contained in this appendix presents an overview of both the development and deployment architecture to enable you to easily understand its components. In this way, you can more readily understand how to use the power and capabilities of Visual InterDev and how to formulate your team when developing a Web-based application.

Development Architecture

The first part of this appendix provides an overview of the Visual InterDev development architecture. You have already gained an understanding of how to use the features of Visual InterDev as well as the supporting technologies to build your Web-based application. Figure C.1 depicts the development environment of Visual InterDev that supports this effort.

Figure C.1.

The Visual InterDev development architecture environment.

As shown in Figure C.1, the developer simultaneously connects to the database and web server during the development process. The developer uses the web server to construct and integrate HTML web pages, Active Server Pages, and Active Server Components as well as other components such as Java applets and applications. The developer uses the Visual Data Tools contained in Visual InterDev to connect to the database server to build the database components. The web pages and application can be previewed and tested by using the browser on the client developer machine. This architecture supports a very rapid and iterative development process for your application development environment. This model changes somewhat as the process moves from development to testing, as explained in the next section.

Testing Architecture

You will want to use a slightly different model to test your Web-based application. The testing environment should simulate the production environment so that you can determine how your application will respond when it's deployed to your users. Figure C.2 illustrates the testing architecture environment for Visual InterDev.

Figure C.2.

The Visual InterDev testing architecture environment.

In this model, the developer tests the application without using the direct connection to the database. Instead, the developer tests the application by requesting both web pages and data through the web server. This process emulates how a user will request information from the application when it is deployed. In this way, the developer can test both the transfer of content information as well as the communication between the web server and database server. The transfer of information between the client, the web server, and the database server is crucial to the success of the application. During this phase, the direct database connection between the client machine and the database server still exists. The developer can use this connection while testing the application to make any changes to the database components or to test specific SQL statements and their results. Once the application has properly been tested, the application can be deployed.

Deployment Architecture

In this model, the user connects strictly with the web server, as shown in Figure C.3.

Figure C.3.

The Visual InterDev production architecture environment.

The user requests information from the web server which in turn makes the determination to retrieve data from the database server. At this point, the database connection exists between the web server and the database server. No direct connection exists between the client machine and the database server. You could say that the client machine in the deployment architecture environment lives vicariously through the web server. In this model, the browser serves as the window to your application's world.