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

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or relationship type.
You can assign a DESCRIPTION attribute to the entity LAST-NAME of type ELEMENT. It is up to you
whether other entities of type ELEMENT also have DESCRIPTION attribute values.
When you request a variable-length attribute value of an entity or relationship you specify, two outcomes
are possible. The first outcome is that the entity or relationship you specify has a value for the attribute
you specify (DESCRIPTION, for instance), and the value is returned. The second possibility is that the
value you requested was never assigned to the entity or relationship you specified, and this is reported as
an error.
Alias Attributes
An alias is an alternate entity name that reflects the entity’s usage in a particular subsystem. In System
Dictionary, an alias is a fixed-length, 32-character attribute that you can assign to any entity or
relationship. Alias attributes never appear in the attribute list of an entity type or relationship type.
Since not every entity or relationship needs aliases, storage space for alias attributes is assigned as
needed.
Table 3-5 shows a list of entities that have IMAGE-ALIAS attribute values. IMAGE-ALIAS, for example,
is an alias attribute that you can use to document an alternate name used in an IMAGE data base. In the
first column are the entity names, with their entity types in the second column. The entity CUSTOMER-
LAST-NAME of type ELEMENT has an IMAGE-ALIAS value of CUST-LAST-NAME. This alternate name
was chosen because IMAGE item names must be 16 characters or less. For the entity ORDERS-MIS-
DATABASE, the IMAGE alias is ORDERS, because IMAGE data base names must be 6 characters or less.
The IMAGE alias of the BURGER_NAME entity is BURGER-NAME, because IMAGE does not allow
underscores in item names.
When you retrieve an alias attribute value of an entity or relationship, a value is always returned. If the
alias exists, a 32-byte value containing the alias name is returned. If the alias does not exist, a blank value
is returned. You can delete an alias attribute value by replacing it with all blanks. When you delete an
alias attribute value, its storage space is released.
Table 4: DESCRIPTION Attribute Values
Entity Entity Type DESCRIPTION
CUSTOMERS FORM Customer info for Admin group
ORDERS IMAGE-DATABASE Order-tracking data base
LAST_NAME ELEMENT Last name is upshifted
DATE RECORD Divided into month/day/year elements
Table 5: IMAGE-ALIAS Attribute Values
Entity Entity Type IMAGE-ALIAS
CUSTOMER-LAST-NAME ELEMENT CUST-LAST-NAME
ORDERS-MIS-DATABASE IMAGE-DATABASE ORDERS
BURGER_NAME ELEMENT BURGER-NAME