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

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OWNER and DATE-CREATED attributes describe the entity definitions themselves--who owns them and
when they were created in the dictionary. The IMAGE-DATASET-TYPE attribute describes each entity's
real-world object, a particular IMAGE data set. In the CUSTOMERS entity, for example, the IMAGE-
DATASET-TYPE attribute indicates that the CUSTOMERS data set is a manual master.
Every entity of type IMAGE-DATASET must have a value for each of these attributes (plus other
attributes not shown in the abbreviated table). You can think of an entity type as defining an imaginary
"table" of entity information. Each "row" in the table corresponds to an entity, including its name and
attribute values. The entity type has a list of associated attributes, and each attribute has a "column" in
the table. When you create an entity, a row is added to the table, and you must specify a value in each
attribute "column" (or allow the attribute value to be defaulted).
When you retrieve an entity, you can request all or part of the conceptual "table" by specifying a complete
or partial attribute list. Only the values corresponding to the attributes you specify are returned. The
complete attribute list of the IMAGE-DATASET entity type is shown in Table 3-2. When you retrieve an
entity of type IMAGE-DATASET, you can request a value for any of these attributes. System Dictionary
supports attributes of type alias and variable-length (described later in this chapter). These attributes are
"free-floating" in that they are never associated with an entity type, but you can assign values for these
attributes to any entity. Not every entity needs alias or variable-length attributes, so the as-needed
method of attribute assignment helps conserve space in the dictionary.
Table 1: Entities of type IMAGE-DATASET
IMAGE-DATASET SCOPE-OWNER DATE-CREATED IMAGE-DATASET-TYPE
CUSTOMERS DA 5/20/86 MANUAL
SALES RON 4/18/86 RELATION
BURGERS KELLY 4/25/86 DETAIL
CHEESE-CODES SAM 7/21/86 AUTOMATIC
Table 2: Core-Set Attribute List Examples
Entity Type Core-Set Attribute List
ELEMENT DATE-CREATED COUNT
DATE-CHANGED DECIMAL
SCOPE-OWNER DISPLAY-LENGTH
SCOPE-CHANGED ELEMENT-TYPE
SENSITIVITY JUSTIFY
ID-NUMBER SIGN
BLANK SYNCHRONIZE
BYTE-LENGTH UNITS