18 1 Hierarchies and Relationships
Figure 1.9 Adding a new element to an XML document. Anoteelement has been
chosen to be added to ageneelement.possible for people to communicate with each other. Individuals must have a
shared conceptual framework in order to communicate, but communication
requires more than just a shared conceptualization; it is also necessary for
the concepts to have names, and these names must be known to the two
individuals who are communicating.
Biochemistry has a rich set of concepts ranging from very generic notions
such aschemicalto exquisitely precise notions such asTumor necrosis factor
alpha-induced protein 3. Concepts are typically organized into hierarchies to
capture at least some of the relationships between them. XML document
hierarchies are a means by which one can represent such hierarchical organi-