Catalogues are constructed as a hierarchy of elements. Each element has certain attributes and some may contain further member elements. The complete Catalogue hierarchy is shown in Figure 4:2.: The Catalogue Database Hierarchy.

Note that in any discussion of attributes which may appear in the rest of this chapter, the ‘standard’ attributes of TYPE, NAME, OWNER and LOCK will not be mentioned, as these are common to all the elements described below.

In addition, User Defined Attributes (UDAs) and User Defined Element Types (UDETs) may be used with Catalogue database elements.