OBJECT-ORIENTED XML
As XML implementations become more sophisticated, they also become 
larger and more complex. In order to manage the complexity, XML 
developers need new approaches that can give them a higher-level view 
of the data they are working with. One approach is to use object-
modeling techniques.

OVERVIEW
There are many aspects to object modeling. The obvious first step is to 
decide exactly what are the objects you are modeling. Once you know 
what the objects are, you'll define their particular attributes. 
Finally, you describe the objects' behavior.

WHAT IS AN OBJECT?
An object is just a thing. In fact, the NEW SHORTER OXFORD ENGLISH 
DICTIONARY includes a definition of object as "a material thing that 
can be seen or perceived." This seems like a good start for defining 
your XML objects. Each element in your XML document can be thought of 
as an object. You'll define these as pieces of data, but you must keep 
in mind that objects need to be able to be seen or perceived. A 
customer, an order, and a product are all examples of objects.

A TRIBUTE TO ATTRIBUTES
The same dictionary defines attribute as "an inherent characteristic, 
quality, or feature of a person or thing; a property." This is the same 
application of attribute that can be used when modeling objects. An 
attribute is a piece of information that describes a particular 
property or feature of an object. Once you have defined your objects, 
you'll define the specific properties and features of those objects as 
attributes. For example, a customer may have attributes such as a name 
and account number. An order has attributes such as order number and 
total price. A product has attributes such as product description and 
shipping weight.

BEHAVE YOURSELF
Object behavior is actually two or more related aspects of your 
objects. The first aspect is how your object can operate or be operated 
on. The processes the object can perform might be the internal behavior 
of the object. There is also the behavior of another object that might 
affect a particular object. Consider an example where a customer can 
place an order. The behavior for the customer could be called 
PlaceOrder. The flip side is that an order has the behavior that a 
customer can place it. Because both a customer and an order are needed 
for this behavior, these objects have a defined relationship, or 
association--the other aspect of your objects. Each object can have 
both operational behavior and associative behavior. While these 
behaviors may or may not be part of your actual XML element hierarchy, 
it will help in defining how applications use and process your XML 
data.

SUMMARY
When modeling your information, it may be important to understand the 
high-level abstraction of objects. By conceiving your data as objects 
and applying object-modeling techniques, you will have a greater 
ability to manage growth and complexity.

Brian Schaffner is a Senior Consultant for DMR Consulting, a Fujitsu 
company. He provides architecture, design, and development support for 
DMR's Telcom360 group.

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