ISO/TS 10303-17:2022

TECHNICAL ISO/TS
SPECIFICATION 10303-17
First edition
2022-03
Industrial automation systems
and integration — Product data
representation and exchange —
Part 17:
Description methods: EXPRESS to
SysML CXMI transformation
Systèmes d'automatisation industrielle et intégration —
Représentation et échange de données de produits —
Partie 17: Méthodes de description: Transformation EXPRESS vers
SysML CXMInque
Reference number
ISO/TS 10303-17:2022(E)
© ISO 2022

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ISO/TS 10303-17:2022(E)
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ISO/TS 10303-17:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 2
3.1 Terms related to generic concepts . 2
3.2 Terms related to EXPRESS constructs . 3
3.3 Terms related to SysML constructs . 4
3.4 Abbreviated terms . 6
4 EXPRESS to SysML CXMI. 6
4.1 General . 6
4.2 Presentation conventions . 7
4.3 Common mapping conventions . 8
4.3.1 Reference to external files . 8
4.3.2 Treatment of Xmi:id, xmi:uuid, and UUID . 8
4.3.3 Assumed sysml:Block in fragments . 8
4.3.4 Containment and reference relationships . 9
4.3.5 Used stereotypes to represent EXPRESS concepts . 9
4.3.6 Select type and supertype . 9
4.4 Mapping of a schema . 9
4.5 Mapping of entities . 10
4.5.1 General mapping of an entity . 10
4.5.2 Mapping of abstract supertype . 10
4.5.3 Mapping of entity with one supertype . 11
4.5.4 Mapping of entity with multiple supertypes . 11
4.5.5 Constraints between subtypes .12
4.5.6 Mapping of entity attribute .12
4.5.7 Local rules . 19
4.6 Mapping of global rules . 19
4.7 Mapping of type . 20
4.7.1 Mapping of simple type .20
4.7.2 Mapping of aggregation types . 22
4.7.3 Mapping of nested of aggregation types . 25
4.7.4 Mapping of select type .30
4.7.5 Proxy artefact .33
4.7.6 Mapping of enumeration type . 33
Annex A (normative) Information object registration .36
Annex B (informative) EXPRESS / Information modelling constructs and the equivalent
SysML modelling constructs . .37
Bibliography . 44
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ISO/TS 10303-17:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 184, Automation systems and
integration, Subcommittee SC 4, Industrial data.
A list of all parts in the ISO 10303 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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ISO/TS 10303-17:2022(E)
Introduction
The ISO 10303 series of international standards describe the computer-interpretable representation of
product information in the exchange of product data. The objective is to provide a neutral mechanism
capable of describing product data throughout the life cycle of a product and independent from any
particular system. The nature of this description makes it suitable not only for neutral file exchange,
but also as a basis for implementing and sharing product databases and archiving.
The EXPRESS language and the EXPRESS-G diagrams are specified in ISO 10303-11. It is used to specify
the information requirements of other parts of the ISO 10303 series.
This document is a member of the description methods series. This document specifies a mapping of
[9][10][11]
EXPRESS to SysML CXMI. This document supports the STEP Extended Architecture .
The Object Management Group (OMG) has standardized the XML Metadata Interchange specification
(XMI), and the Canonical XML Metadata Interchange specification (CXMI) that integrates the OMG
Systems Modeling Language (SysML), the OMG Unified Modeling Language (UML), and the World Wide
[12]
Web Consortium (W3C) Extensible Mark-up Language (XML) . SysML inherits the CXMI interchange
capability from UML. CXMI is a mechanism for the interchange of metadata and formal diagrams
between UML-based modeling tools. OMG has also standardized an CXMI compliant interchange
format for the SysML thus specifying a lexical representation of SysML models based on a standardized
metamodel of the SysML.
This document specifies a description method of the STEP parts family, which defines the
transformation of a subset of EXPRESS constructs to SysML. Because the CXMI standard specifies the
XML representation of SysML metamodel constructs, standardizing the mapping of EXPRESS constructs
into SysML constructs supports the representation of EXPRESS schemas as SysML models.
The specified mapping is a one-way transformation from a subset of an EXPRESS schema to a SysML
model represented by an CXMI specification. These limitations make the mapping unsuitable for the
transformation of arbitrary EXPRESS schemas to SysML models.
A detailed knowledge of the of the EXPRESS and SysML languages is useful.
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TECHNICAL SPECIFICATION ISO/TS 10303-17:2022(E)
Industrial automation systems and integration — Product
data representation and exchange —
Part 17:
Description methods: EXPRESS to SysML CXMI
transformation
1 Scope
This document specifies a mapping of EXPRESS (ISO 10303–11) constructs to SysML constructs for
the purpose of representing EXPRESS schemas in SysML models. The specified mapping is a one-way
transformation from an EXPRESS schema to a SysML information model.
The following are within the scope of this document:
— the specification of the transformation of EXPRESS constructs to SysML constructs represented in
CXMI;
— the specification of the transformation of EXPRESS UNIQUE rules to SysML constructs represented
in CXMI;
— the specification of the transformation of derived attributes to implement renaming to SysML
constructs represented in CXMI.
The following are outside the scope of this document:
— the transformation of EXPRESS elements into SysML metamodel constructs that are not used in the
[9][10][11]
STEP Extended Architecture ;
— transformation of EXPRESS FUNCTIONS;
— transformation of EXPRESS-G to SysML diagrams;
— tools, codes, and scripts to transform an EXPRESS schema to SysML CXMI;
— transformation of EXPRESS interface specification;
— SysML constraints transformation from EXPRESS DERIVE attributes, except the ones used for
renaming;
— SysML constraints transformation from EXPRESS SUPERTYPE expressions;
— SysML constraints transformation from EXPRESS GLOBAL rules;
— SysML constraints transformation from EXPRESS WHERE rules.
NOTE EXPRESS DERIVE attributes, EXPRESS SUPERTYPE expressions, EXPRESS GLOBAL rules and
[2]
EXPRESS WHERE rules are transformed into OCL specifications. OCL specifications are integrated in the
SysML model based on a separate process.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
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ISO/TS 10303-17:2022(E)
ISO 10303-11:2004, Industrial automation systems and integration — Product data representation and
exchange — Part 11: Description methods: The EXPRESS language reference manual
ISO/IEC 19505-1:2012, Information technology — Object Management Group Unified Modeling Language
(OMG UML) — Part 1: Infrastructure
ISO/IEC 19509:2014, Information technology — Object Management Group XML Metadata Interchange
(XMI)
ISO/IEC 19514:2017, Information technology — Object management group systems modeling language
(OMG SysML)
3 Terms, definitions and abbreviated terms
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 Terms related to generic concepts
3.1.1
EXPRESS
data specification language that consists of language elements that allow an unambiguous data
definition and specification of constraints on the data defined
Note 1 to entry: The elements of the EXPRESS language are specified in ISO 10303-11.
3.1.2
data
representation of information in a formal manner suitable for communication, interpretation, or
processing by human beings or computers
[SOURCE: ISO 10303-1:2021, 3.1.29]
3.1.3
data model
description of the organization of data in the management information system of an enterprise
[SOURCE: ISO/IEC 2382:2015, 2121422, modified — Notes 1 and 2 to entry were removed.]
3.1.4
information
facts, concepts, or instructions
[SOURCE: ISO 10303-1:2021, 3.1.41]
3.1.5
resulting CXMI
CXMI based on the transformation specification
3.1.6
information model
conceptual model of product data
Note 1 to entry: In ISO 10303, an information model is based on the Object-relationship modeling technique that
organizes the product data as represented in different system aspects.
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ISO/TS 10303-17:2022(E)
Note 2 to entry: In ISO 10303 information models may be developed using EXPRESS modeling language.
EXAMPLE Application Resource Model for ISO 10303-242 Managed model-based 3D engineering.
[SOURCE: ISO 10303-1:2021, 3.1.42 modified to detail the example]
3.2 Terms related to EXPRESS constructs
3.2.1
data type
domain of values
[SOURCE: ISO 10303-11:2004, 3.3.5]
3.2.2
defined data type
domain of values declared by the user with an identifier
3.2.3
entity
class of information defined by common properties
[SOURCE: ISO 10303-11:2004, 3.3.6]
3.2.4
entity data type
representation of an entity
[SOURCE: ISO 10303-11:2004, 3.3.7, modified — The second sentence was removed.]
3.2.5
entity (data type) instance
value of a class of information defined by common properties
3.2.6
enumeration data type
data type that has as its domain a set of names
3.2.7
aggregation data type
data type that has as its domain collections of values of a given base data type, e.g. array, list, bag, and
set
3.2.8
instance
named value
[SOURCE: ISO 10303-11:2004, 3.3.10]
3.2.9
named data type
data type that may be declared in a formal specification, e.g. entity data type (3.2.4) and defined data
type (3.2.2)
3.2.10
interface specification
construct which enables an item declared in one schema to be visible in another. e.g. USE and
REFERENCE
3.2.11
select data type
data type that enables a choice among several named data types
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ISO/TS 10303-17:2022(E)
3.2.12
simple data type
data type that defines the domains of the atomic data units, e.g. number, real, integer, string, Boolean,
logical, and binary
3.2.13
value
unit of data
[SOURCE: ISO 10303-11:2004, 3.3.22]
3.2.14
global rule
restriction or implicit constraint that applies to one or more entities within the scope of a schema
3.2.15
local rule
assertion on the domain of every entity instance (3.2.5)
3.2.16
uniqueness rule
constraint assertions on the domain of an entity attribute or a combination of entity attributes for
which their instances (3.2.8) must not be equal to every instance of the entity (3.2.3)
3.2.17
where rule
restriction constraint assertions on the domain of one or multiple entities and of one or a combination
of these entities’ attributes for every instance (3.2.8) of the entity (3.2.3)
3.3 Terms related to SysML constructs
3.3.1
Canonical XMI
specific constrained format of XMI that minimizes variability and provides more predictable
identification and ordering
Note 1 to entry: A Canonical XMI file is itself a valid XMI file.
Note 2 to entry: The full definition is provided in ISO/IEC 19509:2014, Annex B.
3.3.2
association
classification of a set of tuples representing links between typed model elements
Note 1 to entry: The full definition is provided in ISO/IEC 19505-1:2012,11.5.
3.3.3
auxiliary
stereotype (3.3.12) applied to an abstract block (3.3.4) that has no properties
Note 1 to entry: The full definition is provided in ISO/IEC 19505-1:2012, Clause 22.
3.3.4
block
modular construct used for defining an entity (3.2.3)
Note 1 to entry: Used for defining Application activity model concepts, Application Data Planning objects,
Application Domain Model Business Objects, Core model objects and ARM in SysML Entities. They may include
reference properties, part properties, value properties, and constraints. They may be specializations of other
blocks.
Note 2 to entry: The full definition is provided in ISO/IEC 19514:2017, Clause 8.
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ISO/TS 10303-17:2022(E)
3.3.5
composite aggregation
responsibility for the existence of composed object
Note 1 to entry: If a composite object is deleted, all of its part instances (3.2.8) that are objects are deleted with it.
Note 2 to entry: The full definition is provided in ISO/IEC 19505-1:2012, 11.4.1.
3.3.6
directed association
association (3.3.2) between a collection of source model elements and a collection of target model
elements that is said to be directed from the source elements to the target elements
Note 1 to entry: The full definition is provided in ISO/IEC 19505-1:2012, 7.2.3.3.
3.3.7
enumeration
value type (3.3.16) whose values are enumerated
Note 1 to entry: The full definition is provided in ISO/IEC 19505-1:2012, 10.2.3.3.
3.3.8
enumeration literal
named value for an enumeration (3.3.7)
Note 1 to entry: The full definition is provided in ISO/IEC 19505-1:2012, 10.2.3.3.
3.3.9
data type
type whose instances (3.2.8) are identified only by their value
Note 1 to entry: The full definition is provided in ISO/IEC 19505-1:2012, 10.2.3.1.
3.3.10
generalization
directed relationship between a more general supertype and a more specific subtype
Note 1 to entry: Each Generalization relates a specific Classifier to a more general Classifier. Given a Classifier,
the transitive closure of its general Classifiers is often called its generalizations, and the transitive closure of
its specific Classifiers is called its specializations. The immediate generalizations are also called the Classifier’s
subtype, and where the Classifier is a Class, its supertype.
Note 2 to entry: The full definition is provided in ISO/IEC 19505-1:2012, C.1.1.
3.3.11
primitive type
predefined data type without any substructure
Note 1 to entry: The full definition is provided in ISO/IEC 19505-1:2012, Clause 21.
3.3.12
stereotype
limited kind of metaclass that cannot be used by itself, but which must always be used in conjunction
with one of the metaclasses it extends
Note 1 to entry: The full definition is provided in ISO/IEC 19505-1:2012, 8.3.2.3 paragraph 6.
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ISO/TS 10303-17:2022(E)
3.3.13
part property
property that specifies a part with strong ownership and coincidental lifetime of its containing block
(3.3.4)
Note 1 to entry: It describes a local usage or a role of the typing Block in the context of the containing Block.
Every Part Property has composite aggregation (3.3.5) and is typed by a Block.
Note 2 to entry: The full definition is provided in ISO/IEC 19514:2017, 8.3.2.3 paragraph 6.
3.3.14
reference property
property that specifies a reference of its containing block (3.3.4) to another block
Note 1 to entry: the full definition is provided in ISO/IEC 19514:2017, 8.3.2.3 paragraph 6.
3.3.15
value property
property of a block (3.3.4) that is typed with a value type (3.3.16) stereotype (3.3.12)
Note 1 to entry: The full definition is provided in ISO/IEC 19514:2017, 8.3.2.3, paragraph 6.
3.3.16
value type
stereotype (3.3.12) of UML Data Type that is used to define types of values that may be used to express
information but cannot be identified as the target of any reference
[6]
Note 1 to entry: The full definition is provided in OMG Systems Modeling Language , 8.3.2.14.
3.4 Abbreviated terms
CXMI Canonical XMI
ID IDentifier
OCL Object Constraint Language
OMG Object Management Group
STEP STandard for the Exchange of Product model data
SysML Systems Modeling Language
UML Unified Modeling Language
UUID Universal Unique Identifier
XMI XML Meta-data Interchange
XML eXtensible Markup Language
4 EXPRESS to SysML CXMI
4.1 General
This clause describes the concepts and rules for the transformation mapping from an EXPRESS schema
to a SysML model, which is physically stored in a CXMI file.
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ISO/TS 10303-17:2022(E)
This document shall use the language construct specifications defined in ISO 10303-11, ISO/IEC 19505-1,
ISO/IEC 19514 and ISO/IEC 19509.
NOTE The mapping clauses are sequentially structured to build increasingly complex transformation
definitions.
This document shall be unambiguously identified in an open information system by the code defined in
Annex A.
EXPRESS constructs and the equivalent SysML constructs are presented in a summarized table in
Annex B.
4.2 Presentation conventions
For ease of identification, the fragments of EXPRESS, CXMI, and SysML are presented in separate boxes.
EXAMPLE 1 EXPRESS, CXMI, and SysML representations presented in separate boxes.
EXPRESS:
…

CXMI:
…

SysML:
…

The items significant to support the explanations are formatted using text effects to aid identification
of the equivalent items in the EXPRESS, CXMI, and SysML fragments. When there is more than one
significant item, different text effects are used for the different items. The following text effects are
used:
— Bold;
— Underline;
— Mixed effects.
Triple dots (“…”) are used to hide content not relevant to a fragment. Curly brackets “{xxx}” are used to
contain descriptive words of the content in the resulting CXMI.
EXAMPLE 2 Usage of Bold and Underline text effects to ease the identification of the significant items in
EXPRESS, CXMI, and SysML fragments, and the usage of triple dots “…” and curly brackets “{umlid}”.
EXPRESS:

ENTITY StepEntityName;
…

CXMI:


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ISO/TS 10303-17:2022(E)
  StepEntityName
  …

SysML:
Class <> named StepEntityName

4.3 Common mapping conventions
4.3.1 Reference to external files
All the references in the SysML CXMI fragments are given as xmi:idref which assumes that the
referenced element is contained in the same CXMI file. When the referenced element is in a different
CXMI file the href is used instead. This will be the case for all reference to primitives and may be case
for other references.
type href shall specify a relative reference to element:
CXMI:

  Text
 
  .other tags.


general href shall specify relative reference to element in another CXMI file:
CXMI:

 DateTimeAssignment
 
  
 
  .other tags.

4.3.2 Treatment of Xmi:id, xmi: uuid, and UUID
A CXMI file uses xmi:id value to make references between all kinds of element. An xmi:id may be in an
xmi: idref attribute.
[3]
Xmi: uuid (UUID ), is not relevant to be included in the mapping transformations. After the first
mapping clause, this attribute will be omitted.
4.3.3 Assumed sysml: Block in fragments
For all the fragments that refer to Block, the following shows how a block is defined in the Canonical
XMI. This is not repeated in the remaining examples, where only xmi:type=”uml:Class” is included and
the sysml:Block is assumed:
SysML:
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ISO/TS 10303-17:2022(E)
Class <>

CXMI:

  



  StepEntityName
  .


4.3.4 Containment and reference relationships
The EXPRESS language (ISO 10303-11) does not distinguish between reference relationships and
containment relationships. SysML and XSD support both types of relationship.
A reference relationship is a directed association attribute between two entities. A referenced entity by
an attribute is an entity that may be referenced multiple times, and which exists standalone. Base root
object entities are always referenced, never contained.
A containment relationship is a directed aggregation attribute between two entities. A contained
entity is an entity that is owned by the entity that defines the containment relationship attribute. The
contained entity does not exist if the containing entity does not exist. A simple type is necessarily
contained.
4.3.5 Used stereotypes to represent EXPRESS concepts
Two existing UM
...