PDM-UG: Relationships between external files

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This page belongs to the PDM Usage Guide.

Document_relationship associates, in the given context, two instances of document files. The semantics of the relationship are defined by the attributes name and description of the entity document_relationship. The name attribute of document_relationship defines the relation type. The semantics of the relation types mirror the capability as defined for the relationships between document representations.

Contents

The Instance Model: EXPRESS entities and attributes

The generic structure to establish a relationship between document_files is illustrated in Diagram 51. The semantics of such a relation is identified via document_relationship.name.

Image:Diagram_51_relation_between_document_files.png
Diagram 51: relation between document files

Document relationship

Attributes

  • The name defines the semantics of the document_relationship.
  • The description is an optional text that characterizes the document_relationship.
  • The relating_document contains one of the document file entity types, which is a part of the relationship.
  • The related_document is the other document file, which is part of the relationship. If one attribute is dependent upon the other, this attribute shall be the dependent one.


ENTITY document_relationship Attribute Population Remarks
name type: label = string defines the semantics of the relation (see table below)
description type: text = string OPTIONAL
relating_document entity: document in this context the subtype document_file of document is used
related_document entity: document in this context the subtype document_file of document is used

===Preprocessor Recommendations=== None specified.

===Postprocessor Recommendations=== None specified.

===Related Entities=== A document_relationship entity relates two document_file instances.

Where applicable the following values shall be used:

  • 'addition': specifies that the related document provides supplementary or collateral information with regard to the information provided by the relating document;
  • 'copy': defines a relationship where the related document file is a copy of the relating document file;
  • 'derivation': defines a relationship where the related document file is derived from the relating document file (e.g., a raster image may be derived from a 3D CAD model);
  • 'decomposition': defines a relationship where the related document file is one of potentially more sub documents of the relating document file (e.g., a decomposition of a document into clauses or into several CAD models);
  • 'peer': specifies that the related document provides required information with regard to that provided by the relating document. The peer document is essential for a complete understanding;
  • 'reference': defines a relationship where the related document is referenced from the relating, e.g., a text processor file referencing a CGM file for inclusion as a graphical object in the text document;
  • 'sequence': defines a logical sequence where the related document file comes after the relating document file (e.g., a sequence of clauses);
  • 'substitution': defines a relationship where the related document file replaces the relating document file;
  • 'translation': specifies that the related document_file (file) was generated from the relating document_file (file) with the intent to convey exactly the same information.

Examples: a ‘translation’ can geometry data from one system and presenting in an another systems, such as using Unigraphics geometry data and ‘translating’ in into another format, such as CATIA geometry data. The intent would be to make the geometry shape as close to the same as possible. A ‘translation’ can apply to other types of data as well. A standards document can be produced in WordPerfect and ‘translated’ to a pdf format. The intent is to keep the printable or viewable image of the document exactly the same in both file formats.

The Instance Model: STEP exchange file format (ISO10303 Part 21 syntax)

ISO-10303-21;
HEADER;
FILE_DESCRIPTION((''),'2;1');
FILE_NAME('', '20.08.1999, 13:19:42', (''), (''), '', '', '');
FILE_SCHEMA(('PDM_SCHEMA {1.2}'));
ENDSEC;
DATA;
#10 = PRODUCT_DEFINITION_FORMATION('1', '', #20);
#20 = PRODUCT('doc', 'versioned_doc', 'a managed document', (#40));
#30 = PRODUCT_RELATED_PRODUCT_CATEGORY('document', '', (#20));
#40 = PRODUCT_CONTEXT('', #50, '');
#50 = APPLICATION_CONTEXT('');
#60 = APPLICATION_PROTOCOL_DEFINITION('version 1.2', 'pdm_schema', 2000 , #50);
#80 = PRODUCT_DEFINITION_CONTEXT('digital document definition', #50, '');
#90 = DOCUMENT_FILE('file_1', '', '', #110, '', $);
#100 = DOCUMENT_REPRESENTATION_TYPE('digital', #90);
#110 = DOCUMENT_TYPE('');
#120 = PRODUCT_DEFINITION_WITH_ASSOCIATED_DOCUMENTS('dig_doc', 'digital document for doc', #10, #80, (#90, #130));
#130 = DOCUMENT_FILE('file_2', '', '', #110, '', $);
#140 = DOCUMENT_REPRESENTATION_TYPE('digital', #130);

#150 = DOCUMENT_RELATIONSHIP('sequence','defines a sequence relation', #90,#130);

/* other product data follows */
   
ENDSEC;
END-ISO-10303-21;
Example 50: exchange file for document file relationship
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