4 Information requirements

This clause specifies the information requirements for the Group application module. The information requirements are specified as the Application Reference Model (ARM) of this application module.

NOTE 1  A graphical representation of the information requirements is given in Annex C.

NOTE 2  The mapping specification is specified in 5.1. It shows how the information requirements are met by using common resources and constructs defined or imported in the MIM schema of this application module.

The following EXPRESS specification begins the Group schema.

4.1 ARM type definition

This subclause specifies the ARM type for this application module. The ARM type and definition is specified below.

4.1.1 groupable_item   

The groupable_item type is an extensible list of alternate data types. Additional alternate data types are specified in select data types that extend the groupable_item type.

NOTE   This empty extensible select requires extension in a further module to ensure that entities that refer to it have at least one valid instantiation.

EXPRESS specification:

*)
TYPE groupable_item = EXTENSIBLE GENERIC_ENTITY SELECT;
WHERE
  WR1: NOT ('GROUP_ARM.GROUP' IN TYPEOF(SELF));
END_TYPE;
(*

Formal propositions:

WR1: A groupable_item shall not be a Group or any subtype of Group.

NOTE    Group nesting can be represented using Group_relationship.

4.2 ARM entity definitions

This subclause specifies the ARM entities for this module. Each ARM application entity is an atomic element that embodies a unique application concept and contains attributes specifying the data elements of the entity. The ARM entities and definitions are specified below.

4.2.1 Group   

EXPRESS specification:

*)
ENTITY Group;
  id : OPTIONAL STRING;
  name : STRING;
  description : OPTIONAL STRING;
  elements : SET[0:?] OF groupable_item;
  membership_meaning : OPTIONAL STRING;
END_ENTITY;
(*

Attribute definitions:

id: the identifier that distinguishes the Group. The value of this attribute need not be specified.

name: the word or group of words by which the Group is referred to.

description: the text that provides further information about the Group. The value of this attribute need not be specified.

elements: the groupable_item instances that are included in the Group.

membership_meaning: the string that specifies the meaning or purpose of the inclusion of the members in the Group. The value of this attribute need not be specified.

4.2.2 Group_relationship   

EXPRESS specification:

*)
ENTITY Group_relationship;
  description : OPTIONAL STRING;
  relation_type : STRING;
  relating_group : Group;
  related_group : Group;
END_ENTITY;
(*

Attribute definitions:

description: the text that provides further information about the Group_relationship. The value of this attribute need not be specified.

relation_type: the string that specifies the meaning of the relationship.

Where applicable, the following value shall be used:

• 'hierarchy': the relating group contains the related group.

relating_group: one of the instances of Group that is a part of the relationship.

related_group: the other instance of Group that is a part of the relationship. If one element of the relationship is dependent up on the other, this attribute shall be the dependent one.

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