A requirement diagram is a diagram specially used in

SysML The Systems Modeling Language (SysML) is a general-purpose modeling language for systems engineering applications. It supports the specification, analysis, design, verification and validation of a broad range of systems and systems-of-systems. S ...

in which

requirement In product development and process optimization, a requirement is a singular documented physical or functional need that a particular design, product or process aims to satisfy. It is commonly used in a formal sense in engineering design, includ ...

s and the relations between them and their relationship to other model elements are shown as discussed in the following paragraphs.

Derive requirement relationship

If a requirement is derived from another requirement, their relation is named "derive requirement relationship".

Namespace containment

If a requirement is contained in another requirement, their relation is named "namespace containment".

Satisfy relationship

If a requirement is satisfied by a design element, their relation is named "satisfy relationship".

Copy relationship

If a requirement is a copy of another requirement, their relation is named "copy relationship".

Verify relationship

If there exists a relation between a requirement and a test case verifying this requirement, their relation is named "verify relationship".

Test case

A test case is defined by a flow checking whether the system under consideration satisfies a requirement.

Refine relationship

If a requirement is refined by other requirements / model elements, the relation is named "refine relationship".

Trace relationship

If there exists a relation between a requirement and an arbitrary model element traced by this requirement, their relation is named "trace relationship".

References

*{{cite book , first= Tim , last = Weilkiens , year = 2008 , url = http://www.system-modeling.com , title = Systems Engineering with SysML/UML: Modeling, Analysis, Design , publisher = Morgan Kaufmann / The OMG Press , isbn=0-12-374274-9 Systems Modeling Language Software requirements Systems engineering