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

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default value to each entity, happens during restructuring when the dictionary is closed. (Restructuring of
the dictionary is discussed later in this chapter.)
Similarly, when you delete an entity-type-attribute association, System Dictionary must remove the
corresponding attribute value from each entity of the affected type.
Relationship-Type-Attribute Associations
Relationship types are templates for defining the attribute values of relationships. When you create or
delete a relationship-type-attribute association, the template is changed, and a corresponding change must
be made in each relationship of the affected type.
Naming Mechanisms
System Dictionary provides a variety of naming conventions that support the definition of the following:
• Modifiable and non-modifiable names
• Alternate entity names called synonyms
• Subsystem-related names called aliases
• Internal numbers that programmers can use
A discussion of these naming mechanisms follows.
Internal and External Names
Every dictionary definition or structure that you can name has two names, an internal name and an
external name. The internal name is a stable, non-modifiable name, while the external name can be
changed. You can also modify the external names of core set structures. This allows the dictionary to be
customized to meet the requirements of a particular application, or localized to your native language,
while still retaining a compatible set of internal names.
When the dictionary is open, you specify a name mode, either internal or external. If you select internal
name mode, all definitions and structures are accessed by their internal names only. In external name
mode, you can see only external names.
Primary Names
In System Dictionary, a primary name is the name of an entity as opposed to its synonyms or aliases.
Since an entity has two names--internal and external--there are actually two primary names for each
entity. In internal name mode, an entity’s primary name is its internal name. In external name mode, an
entity’s primary name is its external name. The primary name of the entity is the name returned when
System Dictionary returns an entity name.
Synonyms
A synonym is an alternate name that uniquely identifies an entity. An entity may have multiple
synonyms, but a synonym can refer to only one entity. You can think of a synonym as a "pointer" that
points to an entity’s primary name. All synonyms of a given entity, point to the same primary name. You
can use synonyms in any context where entity names are allowed. You can modify, delete, or retrieve an
existing entity by using the synonym in place of the entity name.