UML DataType vs SysMLv1 ValueType

Gallery

Tutorial

TRAIL: Webel's ultimate guide to Systems Modeling Language (v1) with MagicDraw/Cameo

Section

08:02: The SysML ValueType, Unit, and using values

Tags and keywords

Topic level

UML keywords

SysML keywords

ValueType::unit

Slide kind

UML Profile Diagram

A ValueType is a special extension of the UML DataType:

UML-2.5.1: 'DataTypes model Types whose instances are distinguished only by their value'

UML-2.5.1: 'A DataType is a kind of Classifier. DataType differs from Class in that instances of a DataType are identified only by their value. All instances of a DataType with the same value are considered to be equal instances.'

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Please note again that:

SysML-1.6: 'In SysML, unless you MUST use a DataType or PrimitiveType from an existing ModelLibrary or Profile, you SHOULD probably be using a ValueType, Enumeration ValueType, or SysML PrimitiveValueType instead so that it integrates with the value system of SysML.'

Note that, in general, a DataType, and thus a ValueType, being a Classifier, may have Features such as Operations and substructure:

SysML-1.6: 'A SysML ValueType may define its own properties and/or operations, just as for a UML DataType.'

But see next about PrimitiveTypes.

Up next

Structured vs Primitive DataType

Notes

[TIP]{STRONG} In SysML, unless you MUST use a DataType or PrimitiveType from an existing ModelLibrary or Profile, you SHOULD probably be using a ValueType, Enumeration ValueType, or SysML PrimitiveValueType instead so that it integrates with the value system of SysML.

[CAVEAT] The SysML Complex "primitive" ValueType does in fact have substructure: realPart:Real and imaginaryPart:Real

Snippets (quotes/extracts)

[UML-2.5.1] DataTypes model Types whose instances are distinguished only by their value

[UML-2.5.1] A PrimitiveType defines a predefined DataType, without any substructure. A PrimitiveType may have algebra and operations defined outside of UML, for example, mathematically.

[SysML-1.6] Value types may be used to type properties, operation parameters, or potentially other elements within SysML.

[SysML-1.6] Although SysML indirectly imports the UML 2 PrimitiveTypes library ... due to the transitivity of package import, SysML provides a PrimitiveValueTypes model library that systems engineers can extend via SysML’s ValueType stereotype.

[SysML-1.6] SysML defines ValueType as a stereotype of UML DataType to establish a more neutral term for system values that may never be given a concrete data representation.

[SysML-1.6] SysML ValueType adds an ability to carry a unit of measure and quantity kind associated with the value.

[UML-2.5.1] Features represent structural and behavioral characteristics of Classifiers.

[SysML-1.6] A SysML ValueType may define its own properties and/or operations, just as for a UML DataType.

[UML-2.5.1] A DataType is a kind of Classifier. DataType differs from Class in that instances of a DataType are identified only by their value. All instances of a DataType with the same value are considered to be equal instances.

Visit also

Visit also (backlinks)

SysMLv1.7/fUMLv1.4: Cameo Simulation Toolkit v2024x: Using an extending Enumeration literal as a parameter argument value runs but a WARN is issued.

Related slides (includes other tutorials)

Figure 8-4: Abstract syntax extensions for SysML value types

Figure 8-10: Model library for primitive value types

Related slides (backlinks, includes other tutorials)

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