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

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Special Attributes
Every entity type and relationship type has a set of special attributes automatically associated with it as
part of the process by which it is created. The set of attributes is not the same for entity types and
relationship types. Most of these attributes have values automatically inserted when you create an
occurrence. A typical example of this is the attribute date-created. This attribute is automatically
associated with every entity type and relationship type as it is created, and whenever an entity or a
relationship is created, the current date is assigned as the value for that attribute. The following
attributes are designated special attributes:
Some characteristics that make these attributes "special" are:
• * They are built into every core set entity type and relationship type.
• If you extend the dictionary by creating new entity types and relationship types, System Dictionary au-
tomatically assigns these attributes to them, and they cannot be removed later.
• You cannot add the id-number attribute to a relationship type, and you cannot add the relationship-po-
sition attribute to an entity type.
• When you create or modify an entity or relationship, you cannot assign values to scope-changed, date-
created, and date-changed, because these attributes are managed exclusively by System Dictionary. Al-
so, you cannot assign a value to the scope-owner attribute when you create an entity or relationship;
System Dictionary sets this attribute. You can, however, assign an existing entity or relationship to a
new scope-owner by modifying its scope-owner attribute.
Type-Attribute Associations
You can assign an attribute of type Boolean, character, floating, or integer to any entity type or
relationship type. This is referred to as creating a type-attribute association. When an attribute is
associated with an entity type or relationship type, all entities or relationships of that type must have a
value for that attribute. Type-attribute associations build the attribute lists of entity types and
relationship types.
System Dictionary has a built-in set of type-attribute associations. These type-attribute associations are
part of the core set and cannot be deleted. You can extend the dictionary by creating other type-attribute
associations. You can add attributes to core set entity types and relationship types or to new entity types
and relationship types. You can later remove these associations from the extended set.
Entity-Type-Attribute Associations
Entity types are templates for defining the set of attribute values in each entity of that type. When you
create a type-attribute association, the template is changed and a corresponding change must be made in
the attribute values of each entity of that type. The change, which involves assigning the attribute’s
Special Attributes for Entity Types Special Attributes for Relationship Types
scope-owner scope-owner
date-created date-created
date-changed date-changed
scope-changed scope-changed
sensitivity sensitivity
id-number relationship-position