About UCM

Unified Change Management (UCM) is a process that supports software project teams in managing their work. UCM uses Rational® ClearCase® and (optionally) Rational ClearQuest® to automate the tasks of software configuration management and defect and change tracking.

UCM organizes work around three development concepts:

Projects

Typically, the work done by software development teams is organized into projects, each of which can have subprojects. Organizing work by project serves three purposes:

The key advantage of UCM as it is implemented in Rational ClearCase and Rational ClearQuest is that the project is a formal software object that allows a higher degree of automation and security. When developers join a UCM project, their workspace is automatically populated with the right versions of the files and directories they need.

Components and component baselines

UCM uses components to organize and identify the versions of files and directories that constitute a reusable piece of your system architecture. A component baseline selects one version of each file in the component. Baselines provide a more stable and reliable mechanism for identifying the files associated with a component than does the practice of labeling. A label can be attached to new files, moved to new versions, or removed from selected files.

After a baseline is created, it cannot be changed. You can be certain that the baseline will always refer to the same version of each file in the component. You can then use baselines to define higher-level configurations. An entire system can be assembled from a set of component baselines.

Activities

UCM uses an activity-based change management model. Changes to files are grouped according to the reason for the change. When you check out a file, a window opens and you specify the reason for making changes to the file by entering a one-line description in the Activity field. You can either select from a list of existing activities or create a new activity.

If UCM is enabled for Rational ClearQuest, an activity can also be a defect or an enhancement request, depending on how rigorous your defect and change tracking process needs to be. UCM supports these types of activities and any others that you define.

This model requires developers to indicate why they are making changes before they check out files. It also integrates the files associated with the change as a single, consistent whole. For example, if you are fixing a defect, you might need to modify a C file and a header file. UCM associates the files with a single activity object in the change management system. When you are finished with your work, you can check in all files by checking in the activity. UCM moves changes through the system at the activity level. When you are ready to integrate your changes into the project, you can deliver the activity.

Activities and baselines work in combination. After a component has been modified by a number of developers, a new baseline is created. By using activities and baselines, you can automate the process of identifying the differences between baselines. This comparison produces both a list of the files that have changed and a list of activities. This information allows you to generate release notes and assist testers in determining the necessary regression tests to run after the nightly build.

For more information

For more information about UCM, see the IBM Rational ClearCase Information Center.

Related tasks
Managing Visual Studio Projects with ClearCase Views
Setting UCM Activities
Delivering Activities
Creating a New Baseline
Getting Started with the Rational Software Integration
Developing Software with UCM in Visual Studio
Related information
Setting Up UCM Work Areas
Displaying ClearCase Views in Front Desk
Working on Activities
Rebasing Work Areas