HP System Dictionary/XL General Reference Manual Vol 1 (32256-90004)

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Figure 3-4. Relationship Types vs. Relationships
Specifying Relationship Classes
In System Dictionary, a relationship type and, consequently, all relationships belonging to the type are
qualified by a relationship class that describes the connection or action of the relationship. The System
Dictionary core set includes relationship types like contains, uses, redefines, and other commonly used
connecting words.
The relationship class is required when more than one relationship type in the dictionary involves the
same ordered list of entity types.
In the core set, for example, there are three relationship types involving element pairs:
ELEMENT contains ELEMENT
ELEMENT redefines ELEMENT
ELEMENT references ELEMENT
The first type describes a parent-child relationship. The second describes elements that share common
storage space in a program. The third type documents an element that references another element, as in a
Pascal type reference. When creating or retrieving relationships defined with non-unique entity type lists
like these, you must specify the relationship class as a qualifier or System Dictionary issues an error.
Remember that a relationship type is an entity-type list paired with a relationship class. Many of these
pairs are built into the dictionary core set, and you can extend the dictionary structure by adding your own
pairs. When you create a relationship, however, you cannot mix and match entity-type lists and