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

4- 42
Sharing Attribute Values
To prevent some of these non-standardization problems, and to allow you to create smaller dictionaries
that are easier to maintain, System Dictionary allows you to create entities and relationships in a local
domain version and link them to existing entities or relationships of the same type in the common domain
version. The linked occurrences will then share the attribute values (and the memory storage space) of the
occurrences they are linked to.
For example, a Dictionary Administrator wants all last names described in the dictionary to be 32
characters long, and therefore creates an entity called LAST-NAME of type ELEMENT in the common
domain version, setting the value of its attribute BYTE-LENGTH, to 32. The DA then instructs the
dictionary users to use this entity for all last names. User #3, however, needs to call the entity by a
different name, creates an entity called CUSTOMER-LAST-NAME and links it to the entity LAST-NAME
in the common domain version. The entity CUSTOMER-LAST-NAME (the local entity) now shares the
attribute value (32) of the attribute BYTE-LENGTH of the entity LAST-NAME (the common entity). Note
that the names of the two linked entities do not have to be the same.
The linking feature, therefore, promotes standardization within the dictionary, and allows you to save
space by using the same set of attributes for multiple entities or relationships. It also makes the
dictionary simpler and easier to maintain by having only one set of attributes to modify, etc. for a set of
linked occurrences, instead of several separate sets. Figure 4-4 below illustrates the common domain and
one local domain, which contain common version CV1 and local version LV1 respectively. The local version
LV1, which is linked to the common version CV1, contains local entity LE1 and local relationship LR1,
which are linked to common entity CE1 and common relationship CR1 respectively, in the common
version. Note that entities called E2 in both the common and local domains are not linked. They are
therefore completely separate entities, and do not share the same attributes, even though they have the
same name. Remember that you must link the local domain version to the common domain version before