Requirement Diagram

Written Date: June 24, 2006
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Besides Textual Analysis and CRC Card Diagram that you are already familar with, the Requirement Diagram from the Systems Modeling Language (SysML) is introduced in VP-UML and SDE for requirements capturing and specification in a more effective and practical approach.

Creating Requirement Diagram

1. To create a Requirement Diagram, select menu File > New Diagram > Requirements Capturing > Requirement Diagram.
2. Alternatively, click on the New Requirement Diagram button on the toolbar.

Drawing Requirement Diagram

Requirement
•  A requirement specifies a capability or condition that a system must satisfy. A requirement may specify a function that a system must perform or a performance condition that a system must fulfill.
Requirement, click once on the Requirement button on the diagram toolbar and then click on the diagram.
A Requirement has several attributes like id, source, text. Besides using the model specification dialog box to fill in the attributes, you can take advantage of our intuitive inline editing interface.
Double-click an attribute or press F2 with an attribute select to start edit it, press the Enter key when finished.
The kind, verifyMethod, risk attributes are enumeration attributes, so you can select from a pre-configured list of values in addition to typing free text. The sets of enumeration values as recommended in the SysML specification are provided as defaults, and you can customize them by referring to the Configuring Requirement Enumerations section later in this page.
You may select different presentation options to show/hide attributes. Just right-click a Requirement and select Presentation Options > Show Attributes and select an option from the popup menu.
The result of selecting different presentation options are shown below:

Model
•  A model acts as a reference to an existing model element in the project. It can be used to represent the source element of a satisfy relationship (which will be mentioned later).
To create a Model, click once on the Model button on the diagram toolbar and then click on the diagram.
To select the referenced model, right-click on the Model and select Open Specification... from the popup menu. In the Model Specification dialog box, click on the ... button next to the Model property.
In the Select Model dialog box, select the Model option, and then select the target model element in the tree (you may click New... to create one).
Commit all dialog boxes. You will see the Model shape is updated to show the referenced model.

TestCase
•  A test case is a behavior or operation that specifies how a requirement is verified. A test case can address one or more verification methods. A test case always returns a verdict.
To create a TestCase, click once on the Test Case button on the diagram toolbar and then click on the diagram.
You can associate a TestCase with a Behavior in UML, which can either be Activity, Interaction or State Machine. To do this, right-click on the TestCase and select Open Specification... from the popup menu. In the Test Case Specification dialog box, click on the ... button next to the Model property.
In the Select Model dialog box, select the Model option, and then select the target model element in the tree (you may click New... to create one).
Commit all dialog boxes. You will see the TestCase shape is updated to show the associated model.

Composition
•  A composition is an association with its aggregation kind set to composition. It can be used to decompose a requirement into sub-requirements.
To create a Composition, click once on the Composition button on the diagram toolbar and then click and drag from the master Requirement to the decomposed Requirement.

Derive
•  A Derive relationship is a trace dependency between a derived requirement and a source requirement, where the derived requirement is generated or inferred from the source requirement.
To create a Derive, click once on the Derive button on the diagram toolbar and then click and drag from the derived Requirement to the source Requirement.

Satisfy
•  A Satisfy relationship is dependency between a supplier requirement and a client model element that fulfills the requirement.
To create a Satisfy, click once on the Satisfy button on the diagram toolbar and then click and drag from the client Model to the supplier Requirement.

Verify
•  A Verify relationship is a trace dependency between a supplier requirement and a client test case that determines whether a system fulfills the requirement.
To create a Verify, click once on the Verify button on the diagram toolbar and then click and drag from the client TestCase to the supplier Requirement.

Configuring Requirement Enumerations

1. Select menu Tools > Configure Requirement Enumerations...
2. The Configure Requirement Enumerations dialog box appears.
  • Types - Select the type of enumeration to configure.
  • Items - Shows the list of items of the enumeration.
  • Add - Click to add a new item.
  • Edit - Click to edit the selected item.
  • Remove - Click to remove selected items.
  • Move up (button with up arrow) - Move selected items upwards.
  • Move down (button with down arrow) - Move selected items downwards.
  • Sample Diagrams

    •  Here are two sample requirement diagrams taken from the SysML specification, drawn using Visual Paradigm for UML.

    Related Resources

    • Know more about Visual Paradigm for UML - A powerful visual UML CASE tool.
    http://www.visual-paradigm.com/product/vpuml/
    • Know more about Smart Development Environment - An UML modeling extension for leading IDEs
    http://www.visual-paradigm.com/product/sde/
    • Get the Free 30 Days Trial of Visual Paradigm for UML
    http://www.visual-paradigm.com/product/vpuml/vpumldownload.jsp
    Software Maintenance VP-UML User's Guide

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    Comments (3)

    written by Baumann on April 6, 2012

    It would be handy to point out that certain features (say "Configure Requirement Enumeration") are only available in Enterprise/Professional/etc..
    I just spent a few minutes trying to find the above mentioned capability, with much confusion - then I noticed the screenshot said "Enterprise edition"

    written by Jick Yeung on April 10, 2012

    Hi Baumann,

    Thank you for your post. This page was written many years ago and the steps to perform certain actions are changed. Sorry about this. The configuration of requirement attributes is supported from Community to Enterprise Edition. To use it, please select "Modeling > Configure Requirements..." from the main menu.

    Hope this helps.

    written by nikos georgosopoulos on March 11, 2014

    One thing that puzzled me was the nice wrapping of text attribute on the screenshots. it turns out that even on the enterprise version that is only manually possible via the cntrl+enter at the end of each line. If possible it would be better off if the system did the wrapping considering the box around the requirement.

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