Question & Answer
Question
Why is there is a distinction between IBM Rational ClearCase views when working in base ClearCase (non-UCM) versus UCM?
Answer
About ClearCase Views
A ClearCase view is a filter into the VOB, and it uses a configuration specification (config spec) to determine what element versions to display.
A view's config spec contains an ordered set of rules for selecting versions of elements.
Note: Only a single version per element can be visible in a view at a time.
Views provide several important functions:
- Access to VOB data
- Workspaces where users can modify VOB data
- Short-Term storage for other data created during the development process
Non-UCM vs UCM Views
While both base ClearCase and UCM use a config spec for version selection, there is a significant difference in how the rules are determined.
A base ClearCase view requires manual, user-specified rules, where as the rules for a UCM view are generated by the stream that it is attached to.
Note: There is a section in the UCM config spec for custom rules, but these rules only allot for read access, and are not intended for general ClearCase functions, such as checkout or add to source control.
For UCM views you can update the config_spec by generating a new config_spec for the stream and then pull it down into the view:
Example:
- cleartool chstream -generate <stream selector>
This generates a new config_spec for the stream - cleartool setcs -current
This pulls the new config_spec into the view
If this is a snapshot view, it will ask you to update the view as the config_spec has changed
Restrictions
Views cannot be shared for both base ClearCase and UCM use.
UCM
Note: Working in a UCM view will return an error if accessing a VOB or component that is not associated with its project:
cleartool: Error: Config spec indicates that checkouts are not allowed for element "<some element>".
- Views can only be used to work on a single stream, under a specific project and in modifiable components that are associated with that project.
- New versions created by a checkin are catalogued in an activity
- Metadata is applied automatically to checked in versions
- Operations, such as cleartool mkactivity, are recorded at the project level
Base ClearCase
Note: ClearCase operations will fail from a non-UCM view that has a config spec set to select versions on a UCM stream:
cleartool: Error: To operate on UCM branch, must be set to an activity and a UCM view.
- Views can work on multiple branches, across different VOBs and can be used in any array of related and unrelated projects
- Checkins performed are recorded as new versions only
- Metadata is optional and applied at the user's (or administrator's) discretion
CAUTION:
UCM components can be shared with a base ClearCase environment.
A separate and unique branching structure must be maintained to avoid conflicting or interfering with the integrity of the UCM project scheme. In this configuration, any new elements or checked in versions will only be visible in there respective views.
This is generally not a recommended configuration due to the risk of damaging the chronological ordering of the UCM project. It is advised to maintain separate VOBs and UCM components for base ClearCase and UCM work, respectively.
Product Documentation
- Views are discussed at length in the IBM Rational ClearCase Administrator's Guide in the following sections
- Rational ClearCase Network Planning and Administration > Views
- Administering Rational ClearCase > Views and View Administration
- IBM Rational ClearCase Managing Software Projects
- IBM Rational ClearCase Developing Software
- IBM Rational ClearCase Building Software
1. The IBM Rational ClearCase Command Reference, or cleartool man <command>, contains detailed information on cleartool mkview and config_spec. These topics contain information general to all views as well as specific to non-UCM and UCM views.
2. For guidance on working in Base ClearCase or UCM:
Documentation
- On-line documentation can be found:
- ClearCase version 7.0 and later documentation:
ClearCase documentation - ClearCase 2003.06:
HTML
PDF LINKS
Related Information
[{"Product":{"code":"SSSH27","label":"Rational ClearCase"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Component":"View: Dynamic","Platform":[{"code":"PF002","label":"AIX"},{"code":"PF010","label":"HP-UX"},{"code":"PF015","label":"IRIX"},{"code":"PF016","label":"Linux"},{"code":"PF027","label":"Solaris"},{"code":"PF033","label":"Windows"}],"Version":"7.0;7.0.1;7.1;7.1.1;7.1.2","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}},{"Product":{"code":"SSSH27","label":"Rational ClearCase"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Component":"View: Snapshot","Platform":[{"code":"","label":""}],"Version":"","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}},{"Product":{"code":"SSSH27","label":"Rational ClearCase"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Component":"View: Snapshot","Platform":[{"code":"","label":""}],"Version":"","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}},{"Product":{"code":"SSSH27","label":"Rational ClearCase"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Component":"UCM: Stream","Platform":[{"code":"","label":""}],"Version":"","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}},{"Product":{"code":"SSSH27","label":"Rational ClearCase"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Component":"UCM: Stream","Platform":[{"code":"","label":""}],"Version":"","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}}]
Was this topic helpful?
Document Information
Modified date:
16 June 2018
UID
swg21237056