Designing the site structure - HTML

The site structure is usually defined in a requirements document. This usually involves a schematic drawing of how the Web site should flow, and which pages are parents and which are children. Figure shows an example of a schematic for a very simple Web site containing only a few pages.

Using UML to define structure
More complex sites require more formal structure definitions. You can use flow charts, or a standardized way to create structure definitions called Unified Modeling Language (UML).

UML is a standardized modeling notation for representing software applications. You can use UML to model the way your Web application is used by each user, or the way each component behaves when interacting with other components.

Schematic for a simple Web site.

UML consists of two broad categories of diagrams:

• Use cases are diagrams that walk the reader through a typical user session at the Web site.
• Sequential and collaboration diagrams provide an abstract view into the relationship between the various objects in the Web site, particularly as they relate to each other. In addition to describing the navigation of a site, these diagrams focus on the application-level functionality of the site so that Java developers and other programmers working on business logic can transition quickly from concept to final production.

Using flow charts to define structure
You can also use your own process for creating a flow chart to define your Web site’s structure. You may not have time to learn UML, or your site’s team may not have the resources for it, in which case most developers simply create their own flow charts by expanding.

You can also use software designed for creating flow charts, such as SmartDraw and Visio (from Microsoft). These programs accelerate the flow-charting process by providing a drag-and-drop visual interface you use to create your charts and export them into graphic formats that you can use in other documents.

A sequential diagram showing a Web application process.

Specifying content
Another consideration when deciding what type of Web server software environment to choose is what kind of content you have. If you have static HTML, it doesn’t matter what kind of environment you have. You can just use the one that is most comfortable to you. If you have database-driven content, you’ll need to include the kind of database you expect to use in your considerations regarding a Web server environment. Several kinds of databases, including several open source varieties, are available, including the following major databases:

• MySQL, which is a popular open source database available on both Windows and UNIX/Linux servers. It’s freely available at www.mysql.com and is nearly as powerful as the expensive databases from commercial vendors. If you are running a Linux box with open source Apache Web server software, this or the somewhat more powerful postgreSQL is the natural route to take for your database environment.
• postgreSQLis another open source database system that has a few more features than MySQL. You can find it at www.postgresql.org. This is also a natural choice if you’re already going the open source route on Web development.
• MS SQL Server is a good choice if you know you’re going to be using a Microsoft-based Web development environment. SQL Server is extremely powerful and fast, and is quite reliable. It also includes a relatively easy-to-use visual interface. It is not, however, inexpensive.
• Oracle has long been considered the standard in robust relational database systems. Oracle is a good choice if you have lots of resources, including the kind of money it takes to administer Oracle correctly. In other words, can your team afford to hire an Oracle Database Administrator (DBA)? Oracle is an expensive product with a cost based on CPU usage and the number of users that actually use the system.
• DB2 is a database system developed by IBM. This is a particularly good fit if you are developing with IBM’s WebSphere Web application development software, which is a Java-based Web development and deployment tool that can hook into any database, but which plays with DB2 especially well. Like Oracle and MS SQL Server, the cost of DB2 is more in line with what a large Web site can afford, and isn’t the kind of investment cash-strapped organizations should consider.