XML in a Nutshell, 3rd Edition

Basic Application Requirements

The first step in designing a new XML application is like the first step in many design methodologies. Before the application can be designed, it is important to determine exactly what needs the application will fulfill. Some basic questions must be answered before proceeding.

Where and how will new documents be created?

Documents that will be created automatically by a software application or database server can be structured differently than those that need to be created by humans using an editor. While software wouldn’t have a problem generating 100 elements with attributes that indicate cross-references, a human being probably would find those expectations frustrating.

If you have an application or a legacy format to which you’re adding XML, you may already have data structures you need to map to the XML. Depending on the other requirements for the application, you may be able to base your XML format on the existing structures. If you’re starting from scratch or need to share the information with other programs that don’t share those structures, you probably need to look at the data itself and build the application creating the XML around the information.

How complex will the document be?

Obviously, the complexity of the data that will be modeled by the XML document has some impact on how the application will be designed. A document containing a few simple element types is much easier to describe than one that contains dozens of different elements with ...