SIMSCRIPT II.5 Programming Language

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AGE 1
DEPENDENTS 2
SOC.SEC.NO. 3
Figure 4-1. Storage of Attributes in a Two-dimensional Array
The entity and attribute structuring permits an entity type, WORKER, to be defined by the statement:
every WORKER has an AGE, a NUMBER.OF.DEPENDENTS
and a SOCIAL.SECURITY.NUMBER
A particular entity of this type may be specified by the value of an implicitly declared global variable
called WORKER, associated with this entity type, and the attribute values associated with this
particular instance of a WORKER may be accessed by references such as:
and
AGE(WORKER)
SOCIAL.SECURITY.NUMBER(WORKER)
Thus, the every statement may define a class of entities, each having similar properties. Every
WORKER entity, of which there may be many, has the same attributes; the actual values of these attributes
may differ for each.
Entities and their attributes are declared in a program preamble by statements of the general form:
every entity name has an attribute name list
Entity and attribute names follow the same naming convention as variables and routines, and each
variable, entity, attribute, and routine name must be unique. To assist in the creation of readable
programs, the words a, the, and some can be used in place of an, as in:
every WORKER has an AGE, some DEPENDENTS and a
SOCIAL.SECURITY.NUMBER
In general, these entity declarations implicitly state the ordering of the attributes within the entity
structure. The data structure associated with each instance of a WORKER entity may be pictured as
shown in figure 4-2.
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