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

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Reference Manual (32256-90001) for instructions to do these operations with the System Dictionary user
interface, or to the HP System Dictionary/XL Intrinsics Reference Manual (32256-90002), if using the
System Dictionary intrinsics.
Relationship Types
A relationship type is a template for defining relationships in the dictionary. A relationship type has three
parts:
• An ordered entity type list.
• A relationship class.
• An attribute list.
Like an entity type, you can think of a relationship type as a category or grouping. Relationships between
IMAGE data bases and data sets are grouped under the relationship type IMAGE-DATABASE contains
IMAGE-DATASET. You can also view a relationship type as a qualifier. The entity type list of the
relationship type qualifies the entities in the relationship. You can have multiple relationships between
entities named ORDERS and INVENTORY provided you qualify them by different relationship types.
Specifying Entity Type Lists
A relationship type does not have a name. It has a list of names representing the entity types involved in
the relationship type. Before you can create a relationship type, all the entity types in the entity type list
must already exist. Also, you cannot delete one of the entity types involved with the relationship type
unless you explicitly request that all the relationship types involving that entity type are to be deleted.
Specifying Relationship Classes
In System Dictionary, a relationship type is qualified by relationship class. The relationship class
describes the connection or action of a relationship. In the relationship type IMAGE-DATABASE contains
IMAGE-DATASET, for example, the relationship class is contains. It expresses the fact that, in each
relationship of this type, the first entity contains the second.
To create a relationship type, you must specify a relationship class that already exists in the dictionary.
You cannot delete a relationship class without explicitly requesting the deletion of all the relationship
types of that class.
Specifying Attribute Lists
Relationship types have attribute lists such that each relationship of the type must have a value for each
attribute in the list. Every relationship type has six built-in attributes, called special attributes (special
attributes are discussed later in this chapter). When you create a relationship type, System Dictionary
automatically associates these attributes with the new relationship type.
In addition, each relationship type may have other attributes associated with it. For each attribute in a
relationship type’s attribute list, there must be a corresponding attribute value assigned to each
relationship of that type. You can add attributes to a relationship type’s attribute list by creating type-
attribute associations (discussed later in this chapter).
Creating and Accessing Relationship Types
You can create, delete, modify, and retrieve relationship types. Detailed instructions for doing these