Chapter 12 Impact Analysis

Introduction to PowerDesigner Impact Analysis

When you want to perform a change on an object, you need to know the impact that this will have on dependant objects in the current model or other models. Most of the time, the impact is a change or a deletion, but it can also be a user-defined event.

You can use impact analysis to evaluate the consequences of changes before performing them or before consolidating a list of changes in the repository.

The following are examples of situations in which impact analysis may be used:

Changing a requirement when development has already started - You want to know which objects will be impacted and which tests this implies. If the requirement was associated with a use case associated with diagrams and analysis classes implemented by components, impact analysis helps you identify which analysis, design and implementation objects will be impacted by the change
Deleting an object - Impact analysis shows which objects will be impacted by the deletion, it also indicates if this object is used by other objects or in other models, if the deletion implies the deletion of other objects that will themselves impact other objects
Consolidating a model - Impact analysis used with the extract dependencies feature, shows which other models will be impacted by the changes you made
Changing the data type of a primary key column - Impact analysis shows which other tables and columns are impacted by the change
Changing the signature of a class operation - Impact analysis shows which child classes override this operation

PowerDesigner helps in these situations, by allowing you to:

Analyze object dependencies and customize the way a change is propagated on depending objects on the Dependencies tab of the Impact Analysis dialog box
Filter the list of changes that you want to review on the List tab
Print or Save the impact analysis in order to review it on the Preview tab