Appendix A: Summary of WebML Elements

WebML element	Brief description	Properties
AND sub-pages	AND sub-pages are used to divide the page into portions. AND sub-pages are contained in a page or in a sub-page.	Nested pages
Area	An area is a container of pages or, recursively, other sub-areas, which can be used to give a hierarchical organization to the site view.	Name Landmark Content: pages, sub-areas Default page or sub-area
Connect unit	A connect unit creates new instances of a relationship.	Name Relationship role Selector of the source entity Selector of the target entity
Create unit	A create unit enables the creation of a new entity instance.	Name Source entity Set of value assignments
Data unit	A data unit publishes a single object of a given entity.	Name Source entity Selector (optional) Included attributes
Delete unit	A delete unit deletes one or more objects of a given entity.	Name Source entity Selector
Disconnect unit	A disconnect unit deletes instances of a relationship.	Name Relationship role Selector of the source entity Selector of the target entity
Entry unit	An entry unit supports form-based data entry.	Name For each field: Name Type Initial value (optional) Modifiability Validity predicate
Generic operation unit	A generic operation unit defines a generic operation: the input and output parameters must be defined by the designer.	Designer-defined
Get unit	A get unit retrieves the value of a global parameter.	Global parameter
Global parameter	A global parameter stores information available to multiple pages for the duration of the session.	Name Type Default value
Hierarchical index...