All these products use the MVC model
pattern (Model View Controller)
the View is the XML sheet template (just the structure)
the controller will see what is asked by the client (the all company employee list or just the name of the prettiest secretary
)
the Model will execute the SQL statement in the DB and populate the View (the template)
if U understand how MVC works , U will improve your knowledge on general content management architecture
A old but very good article about the MVC :
http://www.javaworld.com/javaworld/jw-12-1999/jw-12-ssj-jspmvc.html