Description of the illustration ds_derived_elems.gif
This figure describes how simple and structured data elements derive from base types. The top box displays a data element called ExtendedElement that is derived from a simple data element called BaseElement. The bottom box displays a structured data element called ExtendedStructure that is derived from a structured data element called BaseStructure. The BaseStructure data element includes one child element called Child1. The ExtendedStructure data element derives Child1 from the base element, but this child element is read-only in the ExtendedStructure data element. The figure illustrates how to extend the BaseStructure data element by defining additional child elements in the ExtendedStructure data element. ExtendedStructure includes a simple child data element called Child2 and a structured child data element called AdditionalStructure.