Define Requirements Hierarchy

Using Simulink® Requirements™, you can derive lower-level requirements from higher-level requirements to establish and manage parent-child relationships.

The requirement set is the top level of hierarchy for all requirements. All requirements in Simulink Requirements are contained in requirement sets. Every top-level parent requirement in a requirement set is the first-level hierarchy for that set.

Within a requirement set, you can change the level of individual requirements by using the icons in the Requirements Editor or on the Requirements Browser toolbar. When you promote or demote a requirement with children, the parent-child hierarchical relationship is preserved.

The Implementation and Verification Status metrics for a requirement set are cumulatively aggregated over all the requirements in the set. Each parent requirement in a requirement set derives its metrics from all its child requirements. For more information on the Implementation and Verification Status metrics, see Review Requirement Implementation Status Metrics Data and Review Requirement Verification Status Metrics Data.

Requirement Sets

You can create requirement sets from the Requirements Editor and from the Requirements Browser. Requirement set files (.slreqx) are not inherently associated with your Simulink models.

Requirement sets have built-in properties such as the Filepath and the Revision number associated with them as metadata. Except for the description, properties of the requirement set are read-only and are updated as you work with the requirement set.

Custom Attributes of Requirement Sets

You can define custom attributes for your requirement sets that apply to the requirements they contain. Custom attributes extend the set of properties associated with your requirements Custom attributes for a requirement set can be defined from the Custom Attribute Registries pane of the Requirements Editor.

To define custom attributes for your requirement sets:

  1. Open the Requirements Editor. In the Simulink Editor, select Analysis > Requirements > Requirements Editor.

  2. Select the requirement set and click Add in the Custom Attribute Registries pane.

  3. The Custom Attribute Registration dialog opens. Select the type of custom attribute you want to set for your requirements by using the Type drop-down list. You can specify custom attributes as text fields, check boxes, and combo boxes. You cannot change the properties of the custom attribute after you create it.

To view the custom attributes for your requirements in the spreadsheet, right-click the requirement set and click Select Columns.

When you define a custom attribute as a combobox, the first entry is preset to Unset and it cannot be renamed or deleted. Custom attributes that are imported as referenced requirements from an external document become read-only custom attributes after they are imported. The custom attributes of a requirment set are associated with every individual requirement in the set and removing the custom attributes for a requirement set removes it from all the requirements in the set.

Was this topic helpful?