PDM-UG: 'Sequence' relationships between document versions
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This page belongs to the PDM Usage Guide.
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The Instance Model: EXPRESS entities and attributes
The EXPRESS entities and attributes used to support the requirements of part version sequence history are illustrated in Diagram 32.
Diagram 49: Document Version (sequence) History Instance Diagram
Product definition formation relationship
In this context the entity product_definition_formation_relationship is used to establish sequence relationships between product_definition_formations instances that represent document versions. In consequence, the interpretation of the 'document as product' approach the entity structure is exactly the same as used in the approach for part version history.
Attributes
- The id attribute provides an identifier of the relationship.
- The name attribute specifies this relationship represents a version 'sequence' history.
- The relating_product_definition_formation attribute references the preceding part version .
- The related_product_definition_formation attribute references the subsequent part version.
| ENTITY product_definition_formation_relationship | Attribute Population | Remarks |
| id | type: identifier = string | |
| name | type: label = string | shall be 'sequence' |
| description | type: text = string | OPTIONAL |
| related_product_definition_formation | type : entity = product_definition_formation | subsequent document version |
| relating_product_definition_formation | type : entity = product_definition_formation | preceding document version |
===Preprocessor Recommendations=== The value 'sequence' for the name attribute identifies this as the version sequence history relationship. There is no standard mapping for the description attribute in a product_definition_formation_relationship. The id attribute must be unique with respect to the relationship, but there is no standard mapping for the value.
===Postprocessor Recommendations=== Since there are no standard mapping for the description attributes for a product_definition_formation_relationship, it is recommended that postprocessors not assign any processing significance to this value.
===Related Entities=== None specified.
The Instance Model: STEP exchange file format (ISO10303 Part 21 syntax)
/* primary application context for design assembly life cycle */
#1000 = APPLICATION_CONTEXT('mechanical design');
#220 = PRODUCT_CONTEXT('', #1000, '');
#230 = PRODUCT_DEFINITION_CONTEXT('document definition', #1000, 'design');
/* product type discrimination */
/* #100 identifies the instance #2 as representing a document */
#100=PRODUCT_RELATED_PRODUCT_CATEGORY('document',$,(#2));
/* version A - preceding version */
#2=PRODUCT('11000','a document','description for doc 11000',(#220));
#3=PRODUCT_DEFINITION_FORMATION('A', 'version A for the document',#2);
#4=PRODUCT_DEFINITION('D1','detailed drawing',#3,#230);
/* version B - subsequent version */
#10=PRODUCT_DEFINITION_FORMATION('B', 'version B for the document 11000',#2);
#11=PRODUCT_DEFINITION('D2','detailed drawing',#10,#230);
#16=PRODUCT_DEFINITION_FORMATION_RELATIONSHIP('id','sequence',$,#3,#10);
