PDM-UG: Document Reference
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This page belongs to the PDM Usage Guide.
In 'Document as Product' documents may be associated with product data by reference in a specified role. The base document identification, the document version, or the document representation definition may serve as the point of assignment for a document master to be associated with other product data. It is generally recommended to make a document reference from the level of document version.
Reference of a managed document to product data is accomplished using the entities document_product_equivalence, document, document_type, and applied_document_reference.
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The Instance Model: EXPRESS entities and attributes
The EXPRESS entities and attributes essential to support the requirements of document association with other product data are shown in Diagram 42.
Diagram 42: Document Association to Product Data Instance Diagram
Document product equivalence
The document_product_equivalence entity is a subtype of document_product_association relating a document to a 'product'. It asserts that the related product (or product_definition_formation or product_definition) in this case represents an element of a document master that is assigned as a reference to some other product data. The related_product attribute may refer to an instance of the entity product, product_definition_formation, or product_definition by way of the select type product_or_definition_or_formation. This provides the possibility to assign it to some other product data as a reference when used with the related entities document and applied_document_reference.
Attributes
- The name attribute characterizes the nature of this relationship.
- The description attribute is optional.
- The related_product attribute references the portion of the document master that is being assigned.
- The relating_document attribute has a document entity in a document_reference to some product data.
| ENTITY document_product_equivalence | Attribute Population | Remarks |
| name | type: label = string 'equivalence' | |
| description | type: text = string | OPTIONAL |
| related_product | type: product_or_definition_or_formation (select) | specifies the component of the document master that is the point of association to product data |
| relating_document | type: entity = document |
===Preprocessor Recommendations=== This entity should be used only when the requirement exists to associate a 'Document as Product' with product data. If the 'Document as Product' is not associated with product data, then this entity should not be instantiated.
The relating_document attribute always has a document entity as its value. Additional constraints apply to the document_type entity related to this document by the kind attribute. These prescribe a value for the product_data_type attribute of this document_type entity, correlated with the following select type values of the relating_document:
- Product => 'configuration_controlled_document'
- Product_definition_formation => 'configuration_controlled_document_version'
- Product_definition => 'configuration_controlled_document_definition'
Of these possible options for assignment, it is recommended to assign the 'configuration controlled document version' to product data. When assigned as a reference to a part master identification, it is recommended to assign the document version (product_definition_formation) to the view definition (product_definition) within the part master.
===Postprocessor Recommendations=== When importing an instance of this entity, postprocessors should recognize that the related_product attribute references a 'Document as Product'. The relating_document attribute references an instance of document that exists to allow assignment of the 'Document as Product' to product data.
===Related Entities=== There are no specific related entities.
Document
The document entity is only instantiated as itself when used as the relating_document in a document_product_equivalence relationship. In this role, the document entity is equated with the document master, and works together with the applied_document_reference to support the assignment of managed documents to product data in the STEP PDM Schema.
Attributes
- The kind attribute references a document_type entity.
| ENTITY document | Attribute Population | Remarks |
| id | type: identifier = string | Not to be used for valid user data. |
| name | type: label = string | |
| description | type: text = string | OPTIONAL |
| kind | type: entity = document_type | The product_data_type attribute on this referenced entity is constrained by the entity document_product_equivalence |
===Preprocessor Recommendations=== The document entity is only to be instantiated as itself in this role within the document_product_equivalence. In this case, the document identification is represented by the product master - the attributes on the document entity should not be used for identification of the managed document. It is not instantiated as itself, but as the subtype document_file when used to represent the identification of an external file reference (see External File Identification).
===Postprocessor Recommendations=== The document entity is only a structural element in the assignment of a managed document to product data, along with the entity applied_document_reference. Identification of the managed document is represented by the product master entities according to the 'Document as Product' approach.
===Related Entities=== There are no specific related entities.
Document type
The document_type entity is required for each instance of the entity document. In the given context, this entity is used to indicate that the related document objects are under configuration control. This corresponding usage of document_type is not to be used for a specific document object classification.
Attributes
- The product_data_type attribute describes the type of product data represented by the document entity.
| ENTITY document_type | Attribute Population | Remarks |
| product_data_type | type: identifier = string |
===Preprocessor Recommendations=== In this use for document master identification, the attribute product_data_type is constrained by the entity document_product_equivalence to take one of the following values: 'configuration_controlled_document', 'configuration_controlled_document_version', or 'configuration_controlled_document_definition'.
===Postprocessor Recommendations=== There are no specific postprocessor recommendations.
===Related Entities=== There are no specific related entities.
Applied document reference
The applied_document_reference entity is a subtype of document_reference. It supports the assignment of documents to elements of product data within the select type document_reference_item. Notably, documents may be assigned to the part master view definition (product_definition) or to an individual occurrence of a part definition usage in an assembly structure (product_definition_relationship). Likewise, documents can be associated by versioned_action_request, executed_action or action_method. For additional information, see Versioned action request, Executed action or Action method.
Attributes
- The source attribute is inherited from the supertype document_referen
- The items attribute indicates the elements of product data referenced by the managed document.
| ENTITY applied_document_reference | Attribute Population | Remarks |
| source | type: label = text | |
| assigned_document | type: entity = document | This referenced instance is the only case where the document entity is instantiated as itself, and not the subtype document_file. |
| items | type: document_reference_item = select | SET [1:?] |
===Preprocessor Recommendations=== The inverse attribute role requires the associated entities role_association and object_role be instantiated related to this entity. Preprocessors should support as a minimum the assignment of document to the product_definition representing a part view definition.
===Postprocessor Recommendations=== Postprocessors should as a minimum recognize the assignment of document to the product_definition representing a part view definition.
===Related Entities=== There are no specific related entities.
Role association
The role_association entity provides the item_with_role with a named role string. This is the method to add a role attribute to referenced entities that do not have one defined.
Attributes
- The item_with_role attribute references the role_select type.
- The role attribute references an instance of the entity object_role.
| ENTITY role_association | Attribute Population | Remarks |
| item_with_role | type: role_select = select | |
| role | type: entity = object_role |
===Preprocessor Recommendations=== There are no specific preprocessor recommendations.
===Postprocessor Recommendations=== There are no specific postprocessor recommendations.
===Related Entities=== There are no specific related entities.
Object role
The object_role entity assigns a role to the associated document reference. For example two generic roles that may be used are ‘mandatory’ and ‘informative’. Other role names are allowed when additional knowledge is required that provides specific semantics as to the role of the association between the document and the particular product data. Some of these additional role names are defined in the STEP APs. The two generic role names defined as examples are:
- 'mandatory' means the assignment of the document to the product data is in a mandatory relationship - the document must be taken into account to understand the complete product information.
- 'informative' means the assignment of the document to the product data is an optional relationship - the document may be considered for additional information, but is not required or enforced.
Attributes
- The name attribute indicates the name of the role.
- The description attribute is optional.
| ENTITY object_role | Attribute Population | Remarks |
| name | type: label = string 'mandatory', 'informative', other | Other string values are valid based on requirements found in the APs that utilize the PDM schema |
| Description | type: text = string | OPTIONAL |
===Preprocessor Recommendations=== The name attribute should have the value 'mandatory' or 'informative' if the required semantics to be captured is to indicate if the associated document reference is required or optional, respectively. APs using the PDM schema may have other values for the name attribute that the preprocessor will need to handle.
===Postprocessor Recommendations=== The postprocessor should interpret name attribute as 'mandatory' or 'informative' when the required semantics being exchanged is to indicate if the associated document reference is required or optional, respectively. APs using the PDM schema may have other values for the name attribute that the postprocessor will need to handle.
===Related Entities=== There are no specific related entities.
The Instance Model: STEP exchange file format (ISO10303 Part 21 syntax)
#70=PRODUCT('MP-03-2','my part',$,(#60));
#80=PRODUCT_DEFINITION_FORMATION('03','3rd modification',#70);
#90=PRODUCT_DEFINITION('/NULL',$,#80,#50);
...
#360=DOCUMENT_PRODUCT_EQUIVALENCE('equivalence',$,#370,#280);
#370=DOCUMENT('','',$,#380);
#380=DOCUMENT_TYPE('configuration controlled document version');
#390=APPLIED_DOCUMENT_REFERENCE(#370,'',(#90));
#400=ROLE_ASSOCIATION(#410,#390);
#410=OBJECT_ROLE('mandatory',$);
