7 Basic attribute schema

7.1 General

NOTE 1   The concepts defined in this schema do not provide a generic capability to associate an identification, a name, a description, or a role to product data. They are applied, in order to ensure upward compatibility, in the case where a requirement to add one or more of these kinds of attributes to a particular entity data type has been identified during the revision or amendment process of the standard document in which this entity data type is defined.

NOTE 2   The associated entities are defined in ISO 10303-41, ISO 10303-43 and ISO 10303-44.

Each implementation of an AP that uses this schema and that encodes entity names shall use the encoding specified in Annex A. Each reference to this schema in an open system shall use the identifier encoding specified in Annex B. This schema is illustrated in Annex D using the EXPRESS-G notation.

REFERENCE FROM support_resource_schema    --  ISO 10303-41
  (identifier,
   label,
   text);
(*



NOTE 3   The schemas referenced above are specified in the following parts:

support_resource_schema

ISO 10303-41

NOTE 4   See Annex D for a graphical representation of this schema.

7.2 Fundamental concepts and assumptions

The following concepts are supported by this schema:

• the assignment of an identifier to product data;
• the assignment of a label to product data;
• the assignment of a descriptive text to product data;
• the assignment of a role to an association of management type data with other aspects of product data.

The assignment of an identifier corresponds to the id_attribute entity data type. The entities to which an identifier may be assigned are specified in the id_attribute_select data type. These entities have a derived attribute id. The corresponding identifier value is provided by the get_id_value function. A constraint ensures that there is at most one instance of id_attribute assigned to an instance of an entity in the id_attribute_select type.

The assignment of a name corresponds to the name_attribute entity data type. The entities to which a name may be assigned are specified in the name_attribute_select data type. These entities have a derived attribute name. The corresponding label value is provided by the get_name_value function. A constraint ensures that there is at most one instance of name_attribute assigned to an instance of an entity in the name_attribute_select type.

The assignment of a descriptive text corresponds to the description_attribute entity data type. The entities to which a description may be assigned are specified in the description_attribute_select data type. These entities have a derived attribute description. The corresponding text value is provided by the get_description_value function. A constraint ensures that there is at most one instance of description_attribute assigned to an instance of an entity in the description_attribute_select type.

The assignment of a role corresponds to the role_association entity data type. The entities to which a role may be assigned are specified in the role_select data type. These entities have a derived attribute role. The corresponding object_role is provided by the get_role function. A constraint ensures that there is at most one instance of role_association assigned to an instance of an entity in the role_select type.

7.3 basic_attribute_schema type definitions

7.3.1 description_attribute_select   

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

EXPRESS specification:

*)
TYPE description_attribute_select = EXTENSIBLE GENERIC_ENTITY SELECT;
END_TYPE;
(*

7.3.2 generic_attribute_list_select   

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

EXPRESS specification:

*)
TYPE generic_attribute_list_select = EXTENSIBLE GENERIC_ENTITY SELECT;
END_TYPE;
(*

7.3.3 generic_attribute_select   

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

EXPRESS specification:

*)
TYPE generic_attribute_select = EXTENSIBLE GENERIC_ENTITY SELECT;
END_TYPE;
(*

7.3.4 id_attribute_select   

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

EXPRESS specification:

*)
TYPE id_attribute_select = EXTENSIBLE GENERIC_ENTITY SELECT;
END_TYPE;
(*

7.3.5 name_attribute_select   

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

EXPRESS specification:

*)
TYPE name_attribute_select = EXTENSIBLE GENERIC_ENTITY SELECT;
END_TYPE;
(*

7.3.6 role_select   

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

EXPRESS specification:

*)
TYPE role_select = EXTENSIBLE GENERIC_ENTITY SELECT;
END_TYPE;
(*

7.4 basic_attribute_schema entity definitions

7.4.1 aggregate_id_attribute   

NOTE 1   This entity provides the capability to add an aggregate id attribute to product data using a method that is upwardly compatible with ISO 10303-41:1994 and ISO 10303-43:1994.

EXPRESS specification:

*)
ENTITY aggregate_id_attribute;
  attribute_value : identifier;
  identified_item : SET[1:?] OF id_attribute_select;
END_ENTITY;
(*

Attribute definitions:

attribute_value: the identifier that distinguishes the identified_item.

NOTE 2   The context in which attribute_value is used as a discriminating characteristic can be identified in an annotated Express schema that uses or specializes this entity, or be default, in an agreement of common understanding between partners sharing this information.

identified_item: the collection of items that are identified.

7.4.2 description_attribute   

NOTE    This entity provides the capability to add a description attribute to product data using a method that is upwardly compatible with ISO 10303-41:1994, ISO 10303-43:1994, and ISO 10303-44:1994.

EXPRESS specification:

*)
ENTITY description_attribute;
  attribute_value : text;
  described_item : description_attribute_select;
END_ENTITY;
(*

Attribute definitions:

attribute_value: the text that characterizes the described_item.

described_item: the item that is described.

7.4.3 generic_attribute   

NOTE    This entity provides the capability to define a generic attribute associated with product data using a method that is upwardly compatible with ISO 10303-41:1994, ISO 10303-43:1994, and ISO 10303-44:1994.

EXAMPLE    A person entity data type instance is included in both generic_attribute_select and name_attribute_select. The name attribute of person is provided for the name value.

EXPRESS specification:

*)
ENTITY generic_attribute;
  attribute_name : label;
  attribute_value : text;
END_ENTITY;
(*

Attribute definitions:

attribute_name: the label used to name the generic_attribute.

attribute_value: the text that characterizes the generic_attribute.

7.4.4 generic_attribute_assignment   

NOTE    This entity provides the capability to add a generic attribute to product data using a method that is upwardly compatible with ISO 10303-41:1994 and ISO 10303-43:1994.

EXPRESS specification:

*)
ENTITY generic_attribute_assignment;
  attribute : generic_attribute;
  item_with_attribute : generic_attribute_select;
END_ENTITY;
(*

Attribute definitions:

attribute: the generic_attribute to be associated with the product data.

item_with_attribute: the item to which the attribute is assigned.

7.4.5 generic_attribute_list_assignment   

NOTE    This entity data type provides a capability to add a named list of generic attributes to certain product data entity data types using a method that is upwardly compatible with ISO 10303-41:1994, ISO 10303-43:1994, and ISO 10303-44:1994.

EXPRESS specification:

*)
ENTITY generic_attribute_list_assignment;
  attribute_name : label;
  attributes : LIST[1:?] OF generic_attribute;
  item_with_attribute : generic_attribute_list_select;
END_ENTITY;
(*

Attribute definitions:

attribute_name: the label used to name the list of generic attributes.

attributes: the list of generic_attributes that are assigned to the element of product data.

item_with_attribute: the item to which the attributes are assigned.

7.4.6 id_attribute   

NOTE 1   This entity provides the capability to add an id attribute to product data using a method that is upwardly compatible with ISO 10303-41:1994 and ISO 10303-43:1994.

EXPRESS specification:

*)
ENTITY id_attribute;
  attribute_value : identifier;
  identified_item : id_attribute_select;
END_ENTITY;
(*

Attribute definitions:

attribute_value: the identifier that distinguishes the identified_item.

NOTE 2   The context in which attribute_value is used as a discriminating characteristic can be identified in an annotated Express schema that uses or specializes this entity, or be default, in an agreement of common understanding between partners sharing this information.

identified_item: the item that is identified.

7.4.7 name_attribute   

NOTE    This entity provides the capability to add a name attribute to product data using a method that is upwardly compatible with ISO 10303-41:1994 and ISO 10303-44:1994.

EXPRESS specification:

*)
ENTITY name_attribute;
  attribute_value : label;
  named_item : name_attribute_select;
END_ENTITY;
(*

Attribute definitions:

attribute_value: the label by which the named_item is known.

named_item: the item to which the name is applied.

7.4.8 object_role   

NOTE    This entity provides the capability to add a role attribute to an association of management type data with other aspects of product data using a method that is upwardly compatible with ISO 10303-41:1994.

EXPRESS specification:

*)
ENTITY object_role;
  name : label;
  description : OPTIONAL text;
END_ENTITY;
(*

Attribute definitions:

name: the label by which the object_role is known.

description: the text that characterizes the object_role. The value of the attribute need not be specified.

7.4.9 role_association   

NOTE    This entity data type provides a capability to add a role attribute to certain entity data types that specify associations between product data and administrative or management data. Such entity data types are specified in the management_resources_schema.

EXPRESS specification:

*)
ENTITY role_association;
  role : object_role;
  item_with_role : role_select;
END_ENTITY;
(*

Attribute definitions:

role: the object_role that specifies the purpose of the association of the role_association with product data.

item_with_role: the item to which a role is assigned.

7.5 basic_attribute_schema function definitions

7.5.1 get_aggregate_id_value

If an aggregate_id_attribute references the object, the function will return the value of the attribute_value attribute of this aggregate_id_attribute. Otherwise, the indeterminate value will be returned.

EXPRESS specification:

LOCAL
      aggregate_id_bag : BAG OF aggregate_id_attribute := (USEDIN(obj, 'BASIC_ATTRIBUTE_SCHEMA.' + 'AGGREGATE_ID_ATTRIBUTE.' + 'IDENTIFIED_ITEM'));
    END_LOCAL;

    IF SIZEOF(aggregate_id_bag) = 1 THEN
      RETURN (aggregate_id_bag[1].attribute_value);
    ELSE
      RETURN (?);
    END_IF;

Argument definitions:

obj: (input) the object for which an identifier is determined. This is an input to the function.

7.5.2 get_description_value

If a description_attribute references the object, the function will return the value of the attribute_value attribute of this description_attribute. Otherwise, the indeterminate value will be returned.

EXPRESS specification:

LOCAL
      description_bag : BAG OF description_attribute := (USEDIN(obj, 'BASIC_ATTRIBUTE_SCHEMA.' + 'DESCRIPTION_ATTRIBUTE.' + 'DESCRIBED_ITEM'));
    END_LOCAL;

    IF SIZEOF(description_bag) = 1 THEN
      RETURN (description_bag[1].attribute_value);
    ELSE
      RETURN (?);
    END_IF;

Argument definitions:

obj: (input) the object for which a text is determined. This is an input to the function.

7.5.3 get_id_value

If an id_attribute references the object, the function will return the value of the attribute_value attribute of this id_attribute. Otherwise, the indeterminate value will be returned.

EXPRESS specification:

LOCAL
      id_bag : BAG OF id_attribute := (USEDIN(obj, 'BASIC_ATTRIBUTE_SCHEMA.' + 'ID_ATTRIBUTE.' + 'IDENTIFIED_ITEM'));
    END_LOCAL;

    IF SIZEOF(id_bag) = 1 THEN
      RETURN (id_bag[1].attribute_value);
    ELSE
      RETURN (?);
    END_IF;

Argument definitions:

obj: (input) the object for which an identifier is determined. This is an input to the function.

7.5.4 get_name_value

If a name_attribute references the object, the function will return the value of the attribute_value attribute of this name_attribute. Otherwise, the indeterminate value will be returned.

EXPRESS specification:

LOCAL
      name_bag : BAG OF name_attribute := (USEDIN(obj, 'BASIC_ATTRIBUTE_SCHEMA.' + 'NAME_ATTRIBUTE.' + 'NAMED_ITEM'));
    END_LOCAL;

    IF SIZEOF(name_bag) = 1 THEN
      RETURN (name_bag[1].attribute_value);
    ELSE
      RETURN (?);
    END_IF;

Argument definitions:

obj: the object for which a label is determined. This is an input to the function.

7.5.5 get_role

If a role_association references the object, the function will return the object_role of the role attribute of this role_association. Otherwise, the indeterminate value will be returned.

EXPRESS specification:

LOCAL
      role_bag : BAG OF role_association := (USEDIN(obj, 'BASIC_ATTRIBUTE_SCHEMA.' + 'ROLE_ASSOCIATION.' + 'ITEM_WITH_ROLE'));
    END_LOCAL;

    IF SIZEOF(role_bag) = 1 THEN
      RETURN (role_bag[1].role);
    ELSE
      RETURN (?);
    END_IF;

Argument definitions:

obj: (input) the object for which an object_role is determined. This is an input to the function.

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