PDM-UG: Version History Relationships
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This page belongs to the PDM Usage Guide.
There are two types of relationships between product versions used to represent the version history:
- Sequential relationship: The relating part version is the preceding version and the related part version is the subsequent following version. Both versions must be associated with the same part master base. A part version may have at most one preceding and one subsequent following version.
- Hierarchical relationship: The related part version is a sub version of the relating part version (sometimes referred to as an iteration). Both versions must be associated with the same part master base. Each part version may have at most one super version (parent in the hierarchy). A part version may have an arbitrary number of sub versions (children in the hierarchy). Part versions related by hierarchical relationships may not define cyclic relationships.
Contents |
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 32: Part Version (sequence) History Instance Diagram
Product definition formation relationship
The product_definition_formation_relationship entity generally relates two product_definition_formation instances in a specified relationship type - the identification of the relationship type is given in the name attribute.
Attributes
- The id attribute provides an identifier of the relationship.
- The name attribute specifies this relationship represents a version 'sequence' or 'hierarchy' history.
- The relating_product_definition_formation attribute references the preceding (sequence) or super (hierarchy) part version.
- The related_product_definition_formation attribute references the subsequent (sequence) or sub (hierarchy) part version.
| ENTITY product_definition_formation_relationship | Attribute Population | Remarks |
| id | type: identifier = string | |
| name | type: label = string | shall be 'sequence' or 'hierarchy' |
| description | type: text = string | OPTIONAL |
| relating_product_definition_formation | type : entity = product_definition_formation | preceding part version |
| related_product_definition_formation | Type : entity = product_definition_formation | subsequent part version |
===Preprocessor Recommendations=== The value 'sequence' for the name attribute identifies this as the version sequence history relationship. The value 'hierarchy' for the name attribute identifies this as the version hierarchical 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('part definition', #1000, 'design');
/* part type discrimination */
#100=PRODUCT_RELATED_PRODUCT_CATEGORY('part',$,(#2));
/* version A - preceding version */
#2=PRODUCT('11000','solid cube','description for part 11000',(#220));
#3=PRODUCT_DEFINITION_FORMATION('A', 'version A for solid cube',#2);
#4=PRODUCT_DEFINITION('D1','detailed drawing as planned for STEP conformance testing',#3,#230);
/* version B - subsequent version */
#10=PRODUCT_DEFINITION_FORMATION('B', 'version B for part 11000',#2);
#11=PRODUCT_DEFINITION('D2','detailed drawing',#10,#230);
#16=PRODUCT_DEFINITION_FORMATION_RELATIONSHIP('id','sequence',$,#3,#10);
