Introduction
A simple web page containing product
information for a small company could be created in plain XHTML, however,
whenever product information changes or company details change the web page
will need editing to reflect the changes. When a client requests the page they
always get the same page, unless it has been manually edited/updated by the web
page designer.
Server side scripting provides a mechanism to avoid having
to constantly modify web pages. A combination of html and script is used. The
html provides basic page structure information and fixed elements such as
section headings and explanatory text. The script will cause the server to
access up to date information from a corporate database, insert the current
values into the web page and return the completed page to the client. If the
data in the database changes then the next time the page is retrieved it is
returned with the latest information.
Basic concepts
A simple website only requires a basic web server (HTTP daemon) and from the developers
point of view a mechanism to upload pages onto the server (e.g. an FTP daemon or
a WebDAV based web folder). The
client requests the web page from the server using its URL; the server retrieves
the web page from its location on the system and returns it across the internet
to the client.
A scripted web page in addition requires a script processor on the server. The pages
are stored with a different extension (e.g. .pl for Perl scripts and .aspx for ASP.NET
scripts). When a page is requested, the server knows from the extension that it
need to ask the script processor to interpret the script. The server sends the script
processor the requested page. The script processor executes the script, resulting
in a web page which can be returned to the server and then on to the client.
A script can make use of all the resources available to the server, e.g. the corporate
database; mail server; local files etc. In this way a scripted website can provide
remote clients with access to a complete application environment, such as sales
order processing and dispatch (e.g. Amazon.com).
A web application is simply a combination of linked scripted web pages each providing
part of the functionality of a business system. The only difference between a web
application and a traditional application is that the web application provides a
web page based user interface to a system on a remote server, rather than a user
interface integrated into a single .exe file on a local computer (with network access).
In order to develop a web application you need some sort of development environment
which allows you to:
- Create and edit basic web page layouts
- Create and edit scripts and scripted user interface elements (e.g. text boxes)
- Test the operation of the scripts (without using the production website)
- Link to external resources
- Create databases and links to them
- Publish the website to its destination location on the production website
Visual Web Developer
Visual Web Developer (VWD) is available as a component within Visual Studio 2008
and as a separate 'Express' product. VWD Express 2008 includes
a cut down version of the MSDN Documentation as well as SQL Server 2005 Express.
Visual Studio 2008 also comes with SQL Server 2005 Express but has the complete
MSDN Documentation.
In order to work through this tutorial you should have VWD installed on your
local computer, complete with SQL Server 2005 Express.